How do you multiply a set of integers like -3 ∙ -5 ∙ -2?

In this lesson you will learn to multiply sets of integers by

using the associative property on a number line.

Let’s ReviewLet’s Review

What’s an integer?

Integers include positive and negative whole numbers as well as 0.

...-3, -2, -1, 0, 1, 2, 3 ...

Non-Examples:

-3.1 0.45 -8.6 2

Let’s ReviewLet’s Review

What’s multiplication?

Multiplication is the process of scaling one number by another.

3 ∙ 4 = 12

factor factor product

Multiplication Symbols

3 × 4 3 ∙ 4 3(4) 3n

Let’s ReviewLet’s Review

(6 ∙ 5) ∙ 2 = 60

What’s the associative propertyof multiplication?

With three or more numbers, the product is the same regardless of grouping.

6 ∙ (5 ∙ 2) = 60

(6 ∙ 5) ∙ 2 = 6 ∙ (5 ∙ 2)

Let’s ReviewA Common Mistake

Thinking multiplication properties are different with more than two numbers.

-6 ∙ -4 ∙ -2 = 48 -

Let’s ReviewCore Lesson 3 · -4 · 6(3 · -4) · 6

3 · (-4 · 6)

12-12-72

-24-72

3

-4

Let’s ReviewCore Lesson -5 · -3 · -2(-5 · -3) · -2

-5 · (-3 · -2)

-15 15 30-30

-6 6 30-30

-5

-3

In this lesson you learned to multiply sets of integers by

using the associative property on a number line.

Let’s ReviewGuided Practice

Simplify the following expressions:

-6 ∙( 2 ∙ -1)

(-6 ∙ 2) ∙ -1

Let’s ReviewExtension Activities

Determine whether the answers to the following problems are positive or negative without doing any arithmetic:

A) 1 ∙ -9 ∙ 7B) -4 ∙ -2 ∙ 6C) -5 ∙ -3 ∙ -8D) 7 ∙ 4 ∙ -2E) -3 ∙ 6 ∙ -5 ∙ -4F) -25 ∙ -3 ∙ -18 ∙ -64

Let’s ReviewExtension Activities

Count the number of times the sign changes as you multiply the following numbers.

-1 ∙ -1 ∙ 1 ∙ -1 ∙ 1 ∙ -1 ∙ 1 ∙ 1 ∙ -1

What do you notice about the number of sign changes and the number of negative signs?

Let’s ReviewQuick Quiz

Simplify the following expressions:

5 ∙ (-3 ∙ -7) and (5 ∙ -3) ∙ -7

(-4 ∙ -8) ∙ -3 and -4 ∙( -8 ∙ -3