Pre-Algebra Demystified

ANSWERS

1. 8

2. 14

3.
5

4. 5

5.
4

Multiplication of Integers

For multiplication of integers, there are two basic rules:

Rule 1: To multiply two integers with the same signs, i.e., both are positive

or both are negative, multiply the absolute values of the numbers and give

the answer aþsign.

EXAMPLE

Multiply (þ8)(þ2).

SOLUTION
Multiply 8 2 ¼16. Since both integers are positive, give the answer aþ
(positive) sign. Hence, (þ8)(þ2)¼þ16.

EXAMPLE
Multiplyð
9 Þð
3 Þ:

SOLUTION
Multiply 9 3 ¼27. Since both integers are negative, give the answer aþ
(positive) sign. Hence,ð
9 Þð
3 Þ¼þ27.

Rule 2: To multiply two integers with unlike signs, i.e., one integer is

positive and one integer is negative, multiply the absolute values of the

numbers and give the answer a
(negative) sign.

EXAMPLE

Multiplyð
7 Þ(þ6).

SOLUTION
Multiply 7 6 ¼42 and give the answer a
(negative) sign. Hence,ð
7 Þ
(þ6)¼
42.

CHAPTER 2 Integers 27