Introduction

Excerpts

Introduction
The principal definitions are put at the beginning of the book for convenient reference. They are not to be committed to memory. It is a good plan to have definitions and explanations read aloud in the class, and to encourage pupils to make comments upon them, and ask questions about them.
Introduction
In counting separate objects or in measuring magnitudes, the *standards* by which we count or measure are called **units**.
Introduction
The expression $abc$ must not be confounded with $a + b + c$. $abc$ is a product; $a + b + c$ is a sum.
Introduction
When a sign of operation is omitted in the notation of Arithmetic, it is always the *sign of addition*; but when a sign of operation is omitted in the notation of Algebra, it is always the *sign of multiplication*.
Introduction
The third power of a number is generally called the *cube* of that number; thus, $a^{3}$ is called the *cube* of $a$, because if $a$ denotes the number of units of length in the edge of a cube, $a^{3}$ denotes the number of units of volume in the cube.
Introduction
If a man has $10$ dollars and afterwards collects $3$ dollars and then $2$ dollars, it makes no difference whether he adds the $3$ dollars to his $10$ dollars, and then the $2$ dollars, or puts the $3$ and $2$ dollars together and adds their sum to his $10$ dollars.
Introduction
If a man has $10$ dollars consisting of $2$ five-dollar bills, and has a debt of $3$ dollars to pay, he can pay his debt by giving a five-dollar bill and receiving $2$ dollars.
Introduction
In finding the value of a compound expression the operations indicated *for each term* must be performed *before* the operation indicated by the sign prefixed to the term.

Equations

Introduction
10 + (3 + 2) = 10 + 3 + 2
Removing a parenthesis preceded by + leaves the signs inside it unchanged, so 10 + (3 + 2) equals 10 + 3 + 2.
Introduction
10 + (3 - 2) = 10 + 3 - 2
A parenthesis preceded by + can be removed without changing the sign of the term inside it, so 10 + (3 - 2) equals 10 + 3 - 2.
Introduction
10 - (3 + 2) = 10 - 3 - 2
Subtracting a parenthesized sum is the same as subtracting each of its terms in turn, so 10 - (3 + 2) equals 10 - 3 - 2.
Introduction
10 &- (5 - 2) = 10 - 5 + 2
Subtracting a parenthesized difference flips the sign of each term inside, so 10 - (5 - 2) equals 10 - 5 + 2.
Introduction
4a &= a + a + a + a
The coefficient 4 before a letter means the letter is taken as a term four times, so 4a means a + a + a + a.
Introduction
a^{4} &= a× a× a× a
The exponent 4 means the letter a is taken as a factor four times, so a^4 means a × a × a × a.
Introduction
a (b + c) &= ab + ac
Multiplying a sum by a number is the same as multiplying each term by that number and adding the products.
Introduction
a(b - c) &= ab - ac
Multiplying a difference by a number is the same as multiplying each term by that number and subtracting the products.

Problems

Exercise 1

Exercise 1, problem 1, p. 10
$9 + (3 + 2)$.
Printed answer:
- $14$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 14
Exercise 1, problem 10, p. 10
$9 - (6 + 1)$.
Printed answer:
- $2$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 2
Exercise 1, problem 11, p. 10
$8 - (3 + 2)$.
Printed answer:
- $3$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 3
Exercise 1, problem 12, p. 10
$7 - (3 - 2)$.
Printed answer:
- $6$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 6
Exercise 1, problem 13, p. 10
$9 - (4 + 3)$.
Printed answer:
- $2$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 2
Exercise 1, problem 14, p. 10
$9 - (4 - 3)$.
Printed answer:
- $8$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 8
Exercise 1, problem 15, p. 10
$7 - (5 - 2)$.
Printed answer:
- $4$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 4
Exercise 1, problem 16, p. 10
$7 - (7 - 3)$.
Printed answer:
- $3$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 3
Exercise 1, problem 17, p. 10
$(8 - 6) - 1$.
Printed answer:
- $1$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 1
Exercise 1, problem 18, p. 10
$(3 - 2) - (1 - 1)$.
Printed answer:
- $1$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 1
Exercise 1, problem 19, p. 10
$(7 - 3) - (3 - 2)$.
Printed answer:
- $3$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 3
Exercise 1, problem 2, p. 10
$9 + (3 - 2)$.
Printed answer:
- $10$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 10
Exercise 1, problem 20, p. 10
$(8 - 2) - (5 - 3)$.
Printed answer:
- $4$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 4
Exercise 1, problem 21, p. 10
$15 - (10 - 3 - 2)$.
Printed answer:
- $10$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 10
Exercise 1, problem 3, p. 10
$7 + (5 + 1)$.
Printed answer:
- $13$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 13
Exercise 1, problem 4, p. 10
$7 + (5 - 1)$.
Printed answer:
- $11$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 11
Exercise 1, problem 5, p. 10
$6 + (4 + 3)$.
Printed answer:
- $13$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 13
Exercise 1, problem 6, p. 10
$6 + (4 - 3)$.
Printed answer:
- $7$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 7
Exercise 1, problem 7, p. 10
$3 + (8 - 2)$.
Printed answer:
- $9$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 9
Exercise 1, problem 8, p. 10
$9 - (8 - 6)$.
Printed answer:
- $7$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 7
Exercise 1, problem 9, p. 10
$10 - (9 - 5)$.
Printed answer:
- $6$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 6

Exercise 2

Exercise 2, problem 1, p. 12
$7(8 + 5)$.
Printed answer:
- $91$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 91
Exercise 2, problem 10, p. 12
$2(a^{2} + b^{2})$.
Printed answer:
- $2a^{2} + 2b^{2}$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 2*a**2 + 2*b**2
Exercise 2, problem 11, p. 12
$2(a^{2} - b^{2})$.
Printed answer:
- $2a^{2} - 2b^{2}$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 2*a**2 - 2*b**2
Exercise 2, problem 12, p. 12
$3(ab + c)$.
Printed answer:
- $3ab + 3c$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 3*a*b + 3*c
Exercise 2, problem 13, p. 12
$3(ab - c)$.
Printed answer:
- $3ab - 3c$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 3*a*b - 3*c
Exercise 2, problem 14, p. 12
$3(c - ab)$.
Printed answer:
- $3c - 3ab$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 3*c - 3*a*b
Exercise 2, problem 15, p. 12
$a(b + c)$.
Printed answer:
- $ab + ac$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes a*b + a*c
Exercise 2, problem 16, p. 12
$a(b - c)$.
Printed answer:
- $ab - ac$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes a*b - a*c
Exercise 2, problem 17, p. 12
$3a(b + c)$.
Printed answer:
- $3ab + 3ac$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 3*a*b + 3*a*c
Exercise 2, problem 18, p. 12
$3a(b - c)$.
Printed answer:
- $3ab - 3ac$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 3*a*b - 3*a*c
Exercise 2, problem 19, p. 12
$5a(b^{2} + c)$.
Printed answer:
- $5ab^{2} + 5ac$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 5*a*b**2 + 5*a*c
Exercise 2, problem 2, p. 12
$7(8 - 5)$.
Printed answer:
- $21$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 21
Exercise 2, problem 20, p. 12
$5a(b^{2} - c^{2})$.
Printed answer:
- $5ab^{2} - 5ac^{2}$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 5*a*b**2 - 5*a*c**2
Exercise 2, problem 21, p. 12
$5a^{2}(b^{2} - c)$.
Printed answer:
- $5a^{2}b^{2} - 5a^{2}c$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 5*a**2*b**2 - 5*a**2*c
Exercise 2, problem 3, p. 12
$6(7 + 3)$.
Printed answer:
- $60$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 60
Exercise 2, problem 4, p. 12
$6(7 - 3)$.
Printed answer:
- $24$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 24
Exercise 2, problem 5, p. 12
$8(7 + 5)$.
Printed answer:
- $96$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 96
Exercise 2, problem 6, p. 12
$8(7 - 5)$.
Printed answer:
- $16$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 16
Exercise 2, problem 7, p. 12
$9(6 - 2)$.
Printed answer:
- $36$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 36
Exercise 2, problem 8, p. 12
$4(a + b)$.
Printed answer:
- $4a + 4b$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 4*a + 4*b
Exercise 2, problem 9, p. 12
$4(a - b)$.
Printed answer:
- $4a - 4b$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 4*a - 4*b

Exercise 3

Exercise 3, problem 1, p. 12
$9a$.
Printed answer:
- $63$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 63
On the STU-32 (STU, rpn):
```
9 ENTER 7 ×
```
Calculator: +63E+0; the book prints 63. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 10, p. 12
$\frac{1}{3}abc$.
Printed answer:
- $35$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 35
On the STU-32 (STU, rpn):
```
7 ENTER 5 ×
```
```
3 ×
```
```
3 ÷
```
Calculator: +35E+0; the book prints 35. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 11, p. 12
$\frac{1}{5}ab^{2}c$.
Printed answer:
- $105$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 105
On the STU-32 (STU, rpn):
```
1 ENTER 5 ÷ 7 ×
```
```
5 GOLD x² × 3 ×
```
Calculator: +1050E-1; the book prints 105. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 12, p. 12
$\frac{1}{7}a^{2}bc$.
Printed answer:
- $105$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 105
On the STU-32 (STU, rpn):
```
7 GOLD x²
```
```
5 ×
```
```
3 ×
```
```
7 ÷
```
Calculator: +105E+0; the book prints 105. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 13, p. 12
$4acy^{2}$.
Printed answer:
- $0$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 0
On the STU-32 (STU, rpn):
```
4 ENTER 5 × 0 ×
```
```
3 GOLD x² ×
```
Calculator: +0E-6176; the book prints 0. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 14, p. 12
$3ax^{5}y^{2}$.
Printed answer:
- $135$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 135
On the STU-32 (STU, rpn):
```
3 ENTER 5 ×
```
```
1 ENTER 5 yˣ ×
```
```
3 ENTER 2 yˣ ×
```
Calculator: +135E+0; the book prints 135. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 15, p. 12
$2ab^{2}y$.
Printed answer:
- $120$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 120
On the STU-32 (STU, rpn):
```
2 ENTER 5 ×
```
```
2 GOLD x²
```
```
×
```
```
3 ×
```
Calculator: +120E+0; the book prints 120. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 16, p. 12
$2a^{2}b^{2}c^{2}y^{2}$.
Printed answer:
- $0$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 0
On the STU-32 (STU, rpn):
```
2 ENTER 5 GOLD x² ×
```
```
2 GOLD x² ×
```
```
0 GOLD x² ×
```
```
3 GOLD x² ×
```
Calculator: +0E-6176; the book prints 0. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 17, p. 12
$2a^{2}b^{2}x^{2}y^{2}$.
Printed answer:
- $1800$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 1800
On the STU-32 (STU, rpn):
```
2 ENTER 5 GOLD x² ×
```
```
2 GOLD x² ×
```
```
1 GOLD x² ×
```
```
3 GOLD x² ×
```
Calculator: +1800E+0; the book prints 1800. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 18, p. 12
$2abx^{3}y^{3}$.
Printed answer:
- $540$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 540
On the STU-32 (STU, rpn):
```
2 ENTER 5 ×
```
```
2 ×
```
```
1 ENTER 3 yˣ ×
```
```
3 ENTER 3 yˣ ×
```
Calculator: +540E+0; the book prints 540. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 19, p. 12
$3abcxy$.
Printed answer:
- $0$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 0
On the STU-32 (STU, rpn):
```
3 ENTER 5 ×
```
```
2 ×
```
```
0 ×
```
```
1 ×
```
```
3 ×
```
Calculator: +0E-6176; the book prints 0. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 2, p. 12
$8ab$.
Printed answer:
- $280$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 280
On the STU-32 (STU, rpn):
```
8 ENTER 7 × 5 ×
```
Calculator: +280E+0; the book prints 280. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 20, p. 12
$3abx^{3}y^{2}$.
Printed answer:
- $270$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 270
On the STU-32 (STU, rpn):
```
3 ENTER 5 ×
```
```
2 ×
```
```
1 ENTER 3 yˣ ×
```
```
3 ENTER 2 yˣ ×
```
Calculator: +270E+0; the book prints 270. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 21, p. 12
$3ab^{2}xy^{2}$.
Printed answer:
- $540$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 540
On the STU-32 (STU, rpn):
```
3 ENTER 5 ×
```
```
2 GOLD x² ×
```
```
1 ×
```
```
3 GOLD x² ×
```
Calculator: +540E+0; the book prints 540. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 3, p. 12
$4b^{2}c$.
Printed answer:
- $300$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 300
On the STU-32 (STU, rpn):
```
4 ENTER 5 GOLD x² × 3 ×
```
Calculator: +300E+0; the book prints 300. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 4, p. 12
$2a^{2}$.
Printed answer:
- $98$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 98
On the STU-32 (STU, rpn):
```
7 GOLD x² 2 ×
```
Calculator: +98E+0; the book prints 98. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 5, p. 12
$3c^{3}$.
Printed answer:
- $81$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 81
On the STU-32 (STU, rpn):
```
3 ENTER 3 yˣ
```
```
3 ×
```
Calculator: +81E+0; the book prints 81. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 6, p. 12
$2b^{4}$.
Printed answer:
- $1250$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 1250
On the STU-32 (STU, rpn):
```
5 ENTER 4 yˣ
```
```
2 ×
```
Calculator: +1250E+0; the book prints 1250. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 7, p. 12
$5ac$.
Printed answer:
- $105$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 105
On the STU-32 (STU, rpn):
```
5 ENTER 7 ×
```
```
3 ×
```
Calculator: +105E+0; the book prints 105. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 8, p. 12
$abc$.
Printed answer:
- $105$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 105
On the STU-32 (STU, rpn):
```
7 ENTER 5 ×
```
```
3 ×
```
Calculator: +105E+0; the book prints 105. Run on the calculator core at firmware 628c96c.
Exercise 3, problem 9, p. 12
$abc^{2}$.
Printed answer:
- $315$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 315
On the STU-32 (STU, rpn):
```
7 ENTER 5 ×
```
```
3 GOLD x² ×
```
Calculator: +315E+0; the book prints 315. Run on the calculator core at firmware 628c96c.

Exercise 4

Exercise 4, problem 1, p. 13
$9a - 2bc$.
Printed answer:
- $21$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 21
On the STU-32 (STU, rpn):
```
9 ENTER 5 ×
```
```
2 ENTER 4 × 3 ×
```
```
−
```
Calculator: +21E+0; the book prints 21. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 10, p. 13
$a^{2} - b^{2} - c^{2}$.
Printed answer:
- $0$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 0
On the STU-32 (STU, rpn):
```
5 GOLD x²
```
```
4 GOLD x² −
```
```
3 GOLD x² −
```
Calculator: +0E-6176; the book prints 0. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 11, p. 13
$3(a - b + c)$.
Printed answer:
- $12$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 12
On the STU-32 (STU, rpn):
```
5 ENTER 4 − 3 + 3 ×
```
Calculator: +12E+0; the book prints 12. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 12, p. 13
$6ab - (bc + 8)$.
Printed answer:
- $100$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 100
On the STU-32 (STU, rpn):
```
6 ENTER 5 × 4 ×
```
```
4 ENTER 3 × 8 +
```
```
−
```
Calculator: +100E+0; the book prints 100. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 13, p. 13
$7bc - c^{2} + a$.
Printed answer:
- $80$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 80
On the STU-32 (STU, rpn):
```
7 ENTER 4 ×
```
```
3 ×
```
```
3 GOLD x² −
```
```
5 +
```
Calculator: +80E+0; the book prints 80. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 14, p. 13
$5ac - b^{2} + 3b$.
Printed answer:
- $71$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 71
On the STU-32 (STU, rpn):
```
5 ENTER 5 × 3 ×
```
```
4 GOLD x² −
```
```
3 ENTER 4 × +
```
Calculator: +71E+0; the book prints 71. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 15, p. 13
$4b^{2}c - 5c^{2} - 2b$.
Printed answer:
- $139$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 139
On the STU-32 (STU, rpn):
```
4 ENTER 4 GOLD x² × 3 ×
```
```
5 ENTER 3 GOLD x² × −
```
```
2 ENTER 4 × −
```
Calculator: +139E+0; the book prints 139. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 16, p. 13
$2a + (b + c)$.
Printed answer:
- $17$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 17
On the STU-32 (STU, rpn):
```
2 ENTER 5 ×
```
```
4 ENTER 3 +
```
```
+
```
Calculator: +17E+0; the book prints 17. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 17, p. 13
$b + 2(a - c)$.
Printed answer:
- $8$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 8
On the STU-32 (STU, rpn):
```
5 ENTER 3 −
```
```
2 ×
```
```
4 +
```
Calculator: +8E+0; the book prints 8. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 18, p. 13
$c + 2(a - b)$.
Printed answer:
- $5$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 5
On the STU-32 (STU, rpn):
```
3 ENTER 5 ENTER 4 −
```
```
2 ×
```
```
+
```
Calculator: +5E+0; the book prints 5. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 19, p. 13
$2a - (b + c)$.
Printed answer:
- $3$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 3
On the STU-32 (STU, rpn):
```
2 ENTER 5 ×
```
```
4 ENTER 3 +
```
```
−
```
Calculator: +3E+0; the book prints 3. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 2, p. 13
$ab + 2c$.
Printed answer:
- $26$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 26
On the STU-32 (STU, rpn):
```
5 ENTER 4 ×
```
```
2 ENTER 3 ×
```
```
+
```
Calculator: +26E+0; the book prints 26. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 20, p. 13
$2b - (a - c)$.
Printed answer:
- $6$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 6
On the STU-32 (STU, rpn):
```
2 ENTER 4 ×
```
```
5 ENTER 3 −
```
```
−
```
Calculator: +6E+0; the book prints 6. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 21, p. 13
$2c - (a - b)$.
Printed answer:
- $5$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 5
On the STU-32 (STU, rpn):
```
2 ENTER 3 ×
```
```
5 ENTER 4 −
```
```
−
```
Calculator: +5E+0; the book prints 5. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 22, p. 13
$2c - 5(a - b)$.
Printed answer:
- $1$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 1
On the STU-32 (STU, rpn):
```
2 ENTER 3 ×
```
```
5 ENTER 4 −
```
```
5 ×
```
```
−
```
Calculator: +1E+0; the book prints 1. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 23, p. 13
$2b - 3(a - c)$.
Printed answer:
- $2$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 2
On the STU-32 (STU, rpn):
```
2 ENTER 4 ×
```
```
5 ENTER 3 −
```
```
3 ×
```
```
−
```
Calculator: +2E+0; the book prints 2. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 24, p. 13
$2c - b(a - b)$.
Printed answer:
- $2$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 2
On the STU-32 (STU, rpn):
```
2 ENTER 3 ×
```
```
4 ENTER 5 ENTER 4 − ×
```
```
−
```
Calculator: +2E+0; the book prints 2. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 3, p. 13
$abc+bc$.
Printed answer:
- $72$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 72
On the STU-32 (STU, rpn):
```
5 ENTER 4 × 3 ×
```
```
4 ENTER 3 × +
```
Calculator: +72E+0; the book prints 72. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 4, p. 13
$5ac + 2a$.
Printed answer:
- $85$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 85
On the STU-32 (STU, rpn):
```
5 ENTER 5 × 3 ×
```
```
2 ENTER 5 × +
```
Calculator: +85E+0; the book prints 85. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 5, p. 13
$2abc - 2ac^{2}$.
Printed answer:
- $30$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 30
On the STU-32 (STU, rpn):
```
2 ENTER 5 × 4 × 3 ×
```
```
2 ENTER 5 × 3 GOLD x² ×
```
```
−
```
Calculator: +30E+0; the book prints 30. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 6, p. 13
$ab + bc - ac$.
Printed answer:
- $17$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 17
On the STU-32 (STU, rpn):
```
5 ENTER 4 ×
```
```
4 ENTER 3 ×
```
```
+
```
```
5 ENTER 3 × −
```
Calculator: +17E+0; the book prints 17. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 7, p. 13
$ac - (b + c)$.
Printed answer:
- $8$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 8
On the STU-32 (STU, rpn):
```
5 ENTER 3 ×
```
```
4 ENTER 3 + −
```
Calculator: +8E+0; the book prints 8. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 8, p. 13
$a^{2} + (b^{2} + c^{2})$
Printed answer:
- $50$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 50
On the STU-32 (STU, rpn):
```
5 GOLD x²
```
```
4 GOLD x²
```
```
3 GOLD x²
```
```
+
```
```
+
```
Calculator: +50E+0; the book prints 50. Run on the calculator core at firmware 628c96c.
Exercise 4, problem 9, p. 13
$2a + (2b + 2c)$.
Printed answer:
- $24$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 24
On the STU-32 (STU, rpn):
```
2 ENTER 5 ×
```
```
2 ENTER 4 ×
```
```
2 ENTER 3 ×
```
```
+
```
```
+
```
Calculator: +24E+0; the book prints 24. Run on the calculator core at firmware 628c96c.

Exercise 5

Exercise 5, problem 10, p. 14
If one part of twenty-five is fifteen, what is the other part?
Printed answer:
- (none printed)
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 5, problem 11, p. 14
If one part of $35$ is $x$, what is the other part?
Printed answer:
- $35 - x$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles 35 - x
Exercise 5, problem 12, p. 14
If one part of $x$ is $a$, what is the other part?
Printed answer:
- $x - a$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles x - a
Exercise 5, problem 13, p. 14
How much does ten lack of being twelve?
Printed answer:
- (none printed)
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 5, problem 14, p. 14
How much does $x$ lack of being fourteen?
Printed answer:
- $14 - x$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles 14 - x
Exercise 5, problem 15, p. 14
How much does $x$ lack of being $a$?
Printed answer:
- $a - x$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles a - x
Exercise 5, problem 16, p. 14
If a man walks four miles an hour, how many miles will he walk in three hours?
Printed answer:
- (none printed)
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 5, problem 17, p. 14
If a man walks $y$ miles an hour, how many miles will he walk in $x$ hours?
Printed answer:
- $xy$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles x*y
Exercise 5, problem 18, p. 14
If a man walks $y$ miles an hour, how many hours will it take him to walk $x$ miles?
Printed answer:
- $\dfrac{x}{y}$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles x/y
Exercise 5, problem 1a, p. 14
Read $a + b$; $a - b$; $ab$; $a÷b$.
Printed answer:
- $a$ plus $b$;
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 5, problem 1b, p. 14
Read $a + b$; $a - b$; $ab$; $a÷b$.
Printed answer:
- $a$ minus $b$;
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 5, problem 1c, p. 14
Read $a + b$; $a - b$; $ab$; $a÷b$.
Printed answer:
- $a$ times $b$;
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 5, problem 1d, p. 14
Read $a + b$; $a - b$; $ab$; $a÷b$.
Printed answer:
- $a$ divided by $b$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 5, problem 2, p. 14
Write six increased by four.
Printed answer:
- (none printed)
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 5, problem 3, p. 14
Write $a$ increased by $b$.
Printed answer:
- $a + b$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles a + b
Exercise 5, problem 4, p. 14
Write six diminished by four.
Printed answer:
- (none printed)
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 5, problem 5, p. 14
Write $a$ diminished by $b$.
Printed answer:
- $a - b$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles a - b
Exercise 5, problem 6, p. 14
By how much does twenty-five exceed sixteen?
Printed answer:
- (none printed)
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 5, problem 7, p. 14
By how much does $x$ exceed $y$?
Printed answer:
- $x - y$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles x - y
Exercise 5, problem 8a, p. 14
Write four times three; the fourth power of three.
Printed answer:
- (none printed)
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 5, problem 8b, p. 14
Write four times three; the fourth power of three.
Printed answer:
- (none printed)
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 5, problem 9a, p. 14
Write four times $x$; the fourth power of $x$.
Printed answer:
- $4x$;
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles 4*x
Exercise 5, problem 9b, p. 14
Write four times $x$; the fourth power of $x$.
Printed answer:
- $x^{4}$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles x**4

Exercise 6

Exercise 6, problem 1, p. 15
If the dividend is twenty and the quotient five, what is the divisor?
Printed answer:
- $\frac{20}{5}$.
verified: the printed answer passed a computed check
How it was checked
- solve: passes, with the problem read into an equation {d: 20/5}
On the STU-32 (STU, rpn):
```
20 ENTER 5 ÷
```
Calculator: +4E+0; the book prints 4. Run on the calculator core at firmware 628c96c.
Exercise 6, problem 10, p. 15
If the difference of two numbers is five, and the smaller number is fifteen, what is the greater number?
Printed answer:
- $15 + 5$.
verified: the printed answer passed a computed check
How it was checked
- solve: passes, with the problem read into an equation {g: 15 + 5}
On the STU-32 (STU, rpn):
```
5 ENTER 15 +
```
Calculator: +20E+0; the book prints 20. Run on the calculator core at firmware 628c96c.
Exercise 6, problem 11, p. 15
If the difference of two numbers is eight, and the smaller number is $x$, what is the greater number?
Printed answer:
- $x + 8$.
verified: the printed answer passed a computed check
How it was checked
- solve: passes, with the problem read into an equation {g: x + 8}
Exercise 6, problem 12, p. 15
If the sum of two numbers is $30$, and one of them is $20$, what is the other?
Printed answer:
- $30 - 20$.
verified: the printed answer passed a computed check
How it was checked
- solve: passes, with the problem read into an equation {o: 30 - 20}
On the STU-32 (STU, rpn):
```
30 ENTER 20 −
```
Calculator: +10E+0; the book prints 10. Run on the calculator core at firmware 628c96c.
Exercise 6, problem 13, p. 15
If the sum of two numbers is $x$, and one of them is $10$, what is the other?
Printed answer:
- $x - 10$.
verified: the printed answer passed a computed check
How it was checked
- solve: passes, with the problem read into an equation {o: x - 10}
Exercise 6, problem 14, p. 15
If $100$ contains $x$ ten times, what is the value of $x$?
Printed answer:
- $10$.
verified: the printed answer passed a computed check
How it was checked
- solve: passes, with the problem read into an equation {x: 10}
Exercise 6, problem 2, p. 15
If the dividend is $a$ and the quotient $b$, what is the divisor?
Printed answer:
- $\dfrac{a}{b}$.
verified: the printed answer passed a computed check
How it was checked
- solve: passes, with the problem read into an equation {d: a/b}
Exercise 6, problem 3a, p. 15
If John is twenty years old to-day, how old was he four years ago? How old will he be five years hence?
Printed answer:
- $20 - 4$
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes
Exercise 6, problem 3b, p. 15
If John is twenty years old to-day, how old was he four years ago? How old will he be five years hence?
Printed answer:
- $20 + 5$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes
Exercise 6, problem 4a, p. 15
If James is $x$ years old to-day, how old was he three years ago? How old will he be seven years hence?
Printed answer:
- $(x - 3)$ yr.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 6, problem 4b, p. 15
If James is $x$ years old to-day, how old was he three years ago? How old will he be seven years hence?
Printed answer:
- $(x + 7)$ yr.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 6, problem 5, p. 15
Write four times the expression seven minus five.
Printed answer:
- $4(7 - 5)$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 6, problem 6, p. 15
Write seven times the expression $2x$ minus $y$.
Printed answer:
- $7(2x - y)$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 6, problem 7, p. 15
Write the next integral number above four.
Printed answer:
- $4 + 1$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 6, problem 8a, p. 15
If $x$ is an integral number, write the next integral number above it; the next integral number below it.
Printed answer:
- $x + 1$
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 6, problem 8b, p. 15
If $x$ is an integral number, write the next integral number above it; the next integral number below it.
Printed answer:
- $x - 1$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 6, problem 9, p. 15
What number is less than $20$ by $d$?
Printed answer:
- $20 - d$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles

Exercise 7

Exercise 7, problem 1, p. 16
In $x$ years a man will be $40$ years old; what is his present age?
Printed answer:
- $(40 - x)$ yr.
verified: the printed answer passed a computed check
How it was checked
- solve: passes, with the problem read into an equation 40 - x
Exercise 7, problem 10, p. 16
If $a$ stands for $10$, and $b$ for $2$, find the value of $2(a - 2b)$.
Printed answer:
- $12$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes
Exercise 7, problem 11, p. 16
How many cents in $a$ dollars, $b$ quarters, and $c$ dimes?
Printed answer:
- $100a + 25b + 10c$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 7, problem 12, p. 16
A book-shelf contains French, Latin, and Greek books. There are $100$ books in all, and there are $x$ Latin and $y$ Greek books. How many French books are there?
Printed answer:
- $100 - x - y$.
verified: the printed answer passed a computed check
How it was checked
- solve: passes, with the problem read into an equation 100 - x - y
Exercise 7, problem 13, p. 16
A regiment of men is drawn up in $10$ ranks of $80$ men each, and there are $15$ men over. How many men are there in the regiment?
Printed answer:
- (none printed)
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 7, problem 14, p. 16
A regiment of men is drawn up in $x$ ranks of $y$ men each, and there are $c$ men over. How many men are there in the regiment?
Printed answer:
- $xy + c$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 7, problem 2, p. 16
How old will a man be in $y$ years, if his present age is $a$ years?
Printed answer:
- $(a + y)$ yr.
verified: the printed answer passed a computed check
How it was checked
- solve: passes, with the problem read into an equation a + y
Exercise 7, problem 3, p. 16
What is the value of $x$ if $7x$ equals $28$?
Printed answer:
- $4$.
verified: the printed answer passed a computed check
How it was checked
- solve: passes 4
On the STU-32 (STU, rpn):
```
28 ENTER 7 ÷
```
Calculator: +4E+0; the book prints 4. Run on the calculator core at firmware 628c96c.
Exercise 7, problem 4, p. 16
If it takes $3$ men $4$ days to reap a field, how many days will it take one man to reap it?
Printed answer:
- (none printed)
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 7, problem 5, p. 16
If it takes $a$ men $b$ days to reap a field, how many days will it take one man to reap it?
Printed answer:
- $ab$.
verified: the printed answer passed a computed check
How it was checked
- solve: passes, with the problem read into an equation a*b
Exercise 7, problem 6, p. 16
What is the excess of $5x$ over $3x$?
Printed answer:
- $5x - 3x$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 7, problem 7, p. 16
By how much does $20 - 3$ exceed $(10 + 1)$?
Printed answer:
- (none printed)
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 7, problem 8, p. 16
By how much does $2x - 3$ exceed $(x + 1)$?
Printed answer:
- $2x - 3 - (x + 1)$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles
Exercise 7, problem 9, p. 16
If $x$ stands for $10$, find the value of $4(3x - 20)$.
Printed answer:
- $40$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes

Exercise 8

Exercise 8, problem 1, p. 17
A room is $10$ yards long and $8$ yards wide. In the middle there is a carpet $6$ yards square. How many square yards of oilcloth will be required to cover the rest of the floor?
Printed answer:
- $10 × 8 - 6^{2}$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles 10*8 - 6**2
Exercise 8, problem 10a, p. 17
Write an expression for the sum, and also for the product, of three consecutive numbers of which the least is $n$.
Printed answer:
- $n + (n + 1) + (n + 2)$
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles n + (n + 1) + (n + 2)
Exercise 8, problem 10b, p. 17
Write an expression for the sum, and also for the product, of three consecutive numbers of which the least is $n$.
Printed answer:
- $n(n + 1)(n + 2)$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles n*(n + 1)*(n + 2)
Exercise 8, problem 11, p. 17
The product of two factors is $36$; if one of the factors is $x$, what is the other factor?
Printed answer:
- $\dfrac{36}{x}$.
verified: the printed answer passed a computed check
How it was checked
- solve: passes, with the problem read into an equation 36/x
Exercise 8, problem 12, p. 17
If $d$ is the divisor and $q$ the quotient, what is the dividend?
Printed answer:
- $qd$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles q*d
Exercise 8, problem 13, p. 17
If $d$ is the divisor, $q$ the quotient, and $r$ the remainder, what is the dividend?
Printed answer:
- $qd + r$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles q*d + r
Exercise 8, problem 14, p. 17
If $x$ oranges can be bought for $50$ cents, how many oranges can be bought for $100$ cents?
Printed answer:
- $2x$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles 2*x
Exercise 8, problem 15, p. 17
What is the price in cents of $x$ apples, if they are ten cents a dozen?
Printed answer:
- $\dfrac{10x}{12}$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles 10*x/12
Exercise 8, problem 16, p. 17
If $b$ oranges cost $6$ cents, what will $a$ oranges cost?
Printed answer:
- $\dfrac{6a}{b}$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles 6*a/b
Exercise 8, problem 17, p. 17
How many miles between two places, if a train travelling $m$ miles an hour requires $4$ hours to make the journey?
Printed answer:
- $4m$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles 4*m
Exercise 8, problem 18, p. 17
If a man was $x$ years old $10$ years ago, how many years old will he be $7$ years hence?
Printed answer:
- $x + 17$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles x + 17
Exercise 8, problem 19, p. 17
If a man was $x$ years old $y$ years ago, how many years old will he be $c$ years hence?
Printed answer:
- $x + y + c$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles x + y + c
Exercise 8, problem 2, p. 17
A room is $x$ yards long and $y$ yards wide. In the middle there is a carpet $a$ yards square. How many square yards of oilcloth will be required to cover the rest of the floor?
Printed answer:
- $xy - a^{2}$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles x*y - a**2
Exercise 8, problem 20, p. 17
If a floor is $3x$ yards long and $12$ yards wide, how many square yards does the floor contain?
Printed answer:
- $36x$.
verified: the printed answer passed a computed check
How it was checked
- identity: passes 36*x
Exercise 8, problem 21, p. 17
How many hours will it take to walk $c$ miles, at the rate of one mile in $15$ minutes?
Printed answer:
- $\dfrac{c}{4}$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles c/4
Exercise 8, problem 22, p. 17
Write three consecutive numbers of which $x$ is the middle number.
Printed answer:
- $x - 1$, $x$, $x + 1$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles [x - 1, x, x + 1]
Exercise 8, problem 23, p. 17
If an odd number is represented by $2n + 1$, what will represent the next odd number?
Printed answer:
- $2n + 3$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles 2*n + 3
Exercise 8, problem 3, p. 17
How many rolls of paper $g$ feet long and $k$ feet wide will be required to paper a room, the perimeter of which, after proper allowance is made for doors and windows, is $p$ feet and the height $h$ feet?
Printed answer:
- $\dfrac{ph}{gk}$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles p*h/(g*k)
Exercise 8, problem 4, p. 17
Write six times the square of $m$, plus five $c$ times the expression $d$ plus $b$ minus $a$.
Printed answer:
- $6m^{2} + 5c(d + b - a)$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles 6*m**2 + 5*c*(d + b - a)
Exercise 8, problem 5, p. 17
Write five times the expression two $n$ plus one, diminished by six times the expression $c$ minus $a$ plus $b$.
Printed answer:
- $5(2n + 1) - 6(c - a + b)$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles 5*(2*n + 1) - 6*(c - a + b)
Exercise 8, problem 6, p. 17
A lady bought a dress for $a$ dollars, a cloak for $b$ dollars, two pairs of gloves for $c$ dollars a pair. She gave a hundred-dollar bill in payment. How much money should be returned to her?
Printed answer:
- $$100 - \text{\$(a + b + 2c)$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles 100 - (a + b + 2*c)
Exercise 8, problem 7, p. 17
If a man can perform a piece of work in $4$ days, how much of it can he do in one day?
Printed answer:
- $\frac{1}{4}$.
verified: the printed answer passed a computed check
How it was checked
- evaluate: passes 1/4
Exercise 8, problem 8, p. 17
If a man can perform a piece of work in $x$ days, how much of it can he do in one day?
Printed answer:
- $\dfrac{1}{x}$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles 1/x
Exercise 8, problem 9, p. 17
If A can do a piece of work in $x$ days, B in $y$ days, C in $z$ days, how much of it can they all do in one day, working together?
Printed answer:
- $\dfrac{1}{x} + \dfrac{1}{y} + \dfrac{1}{z}$.
unverified: no computed check settled this one (yet)
How it was checked
- other: not a kind the checker handles 1/x + 1/y + 1/z