Multiplying and Dividing Integers

Example 3.47

Multiply each of the following:

ⓐ $−9⋅3$
ⓑ $−2(−5)$
ⓒ $4(−8)$
ⓓ $7⋅6$

 Solution

ⓐ  $–9⋅3$
Multiply, noting that the signs are different and so the product is negative.

$–27$

ⓑ  $–2(–5)$
Multiply, noting that the signs are the same and so the product is positive.

$10$

ⓒ $4(–8)$
Multiply, noting that the signs are different and so the product is negative.

$–32$

ⓓ  $7⋅6$
The signs are the same, so the product is positive.

$42$

Example 3.49

Divide each of the following:

ⓐ $−27÷3$
ⓑ $−100÷(−4)$

Solution

ⓐ  $–27÷3$
Divide, noting that the signs are different and so the quotient is negative.

$–9$

ⓑ  $–100÷(–4)$
Divide, noting that the signs are the same and so the quotient is positive.

$25$

Try It 3.93