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Exercises Numbers, fractions and percents

Example 3.47 from Prealgebra, 3.4 Multiply and Divide Integers

Multiply and Divide Integers: example 3.47

Multiply each of the following:

ⓐ $−9 \cdot 3$
ⓑ $−2 (−5)$
ⓒ $4 (−8)$
ⓓ $7 \cdot 6$

Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.

Solution

ⓐ

$–9 \cdot 3$

Multiply, noting that the signs are different and so the product is negative. $–27$

Table 3.5

ⓑ

$–2 (–5)$

Multiply, noting that the signs are the same and so the product is positive. $10$

Table 3.6

ⓒ

$4 (–8)$

Multiply, noting that the signs are different and so the product is negative. $–32$

Table 3.7

ⓓ

$7 \cdot 6$

The signs are the same, so the product is positive. $42$

Table 3.8

Your turn

The book's Try It right after this example: same idea, new numbers. Only the answer is given.

Multiply:

ⓐ $−6 \cdot 8$
ⓑ $−4 (−7)$
ⓒ $9 (−7)$
ⓓ $5 \cdot 12$

How did it go?

PreviousSubtract Integers: example 3.46 Next Multiply and Divide Integers: example 3.48

From Prealgebra (1st edition) by OpenStax (Rice University), section 3.4, licensed under CC BY 4.0. Original at openstax.org. We split the solution into steps; the words, numbers and figures are the book's. OpenStax doesn't endorse this site.