Easy Algebra Step-by-Step

26 Easy Algebra Step-by-Step

Multiplication and Division of Signed Numbers

For multiplication of signed numbers, use the following three rules:

Multiplication of Signed Numbers

Rule 5. To multiply two numbers that have the same sign, multiply their

absolute values and keep the product positive.

Rule 6. To multiply two numbers that have

opposite signs, multiply their absolute

values and make the product negative.

Rule 7. The product of 0 and any number is 0.

Problem Find the product.

a. ()))()((

b. ())()(

c. ())()(

d. ())()(

e. ()()

Solution

a. ()))()((

Step 1. Determine which multiplication rule applies.

()− )()(−

The signs are the same (both negative), so use Rule 5.

Step 2. Multiply the absolute values, 3 and 40.

() 3 () 40 = 120

Step 3. Keep the product positive.

()− )()(− = 120

b. ())()(

Step 1. Determine which multiplication rule applies.

() 3 () 40

The signs are the same (both positive), so use Rule 5.

Step 2. Multiply the absolute values, 3 and 40.

()^3 ()^40 =^120

P

When you multiply two positive

or two negative numbers, the

product is always positive no

matter what. Similarly, when

you multiply two numbers that

have opposite signs, the product

is always negative—it doesn’t

matter which number has the

greater absolute value.