The water in a swimming pool decreases two degrees every hour.

How much has the water temperature changed after five hours?

In this lesson you will learn about multiplication with

positive and negative integers by noticing patterns.

Let’s ReviewLet’s Review

Integers include5 12 0

And their opposites-5 -12 0

Multiplication can be written using:4 · 6 4 x 6 (4)(6)

Let’s ReviewA Common Mistake

The meaning of multiplication does not change, we just need to consider the types of numbers we are multiplying.

5 x -2 x -2 -6.5 x 3.4

Let’s ReviewCore Lesson

Let’s take a look at a multiplication pattern….5 x 4 = 20

5 x 3 = 155 x 2 = 105 x 1 = 55 x 0 = 05 x(-1)=-55 x(-2)=-10

Let’s ReviewCore Lesson

5 x 4 = 205 x 3 = 155 x 2 = 105 x 1 = 55 x 0 = 05 x(-1)= -55 x(-2)= -10

Let’s review the pattern…

Leads to negative product here.

One fewer and going down 5 each time…

Let’s ReviewCore Lesson

(-1) x (-2)= +2

Let’s continue the pattern….5 x(-2) = -104 x(-2) = -83 x(-2) = -62 x(-2) = -41 x (-2) = -20 x(-2) = 0

(-2) x (-2)=+4

Let’s ReviewCore LessonLet’s review the pattern….

5 x (-2) = -104 x (-2) = -83 x (-2) = -62 x (-2) = -41 x (-2) = -20 x (-2) = 0(-1) x(-2)= 2(-2) x(-2)= 4

Leads to positive product here.

One fewer and going up 2 each time…

Let’s ReviewA Common Mistake

(-1) x (-2) = -2

(-1) x (-2) = +2

Let’s ReviewCore LessonIf the temperature rises….5 x 2 = 10 degrees

If the temperature does not change5 x 0 = 0 degrees

If the temperature falls…..5 x -2 = -10 degrees

The water in a swimming pool decreases two degrees every hour. How much has

the water temperature changed after five hours?

5 x -2= -10 degrees

In this lesson you have learn about multiplication with

positive and negative integers by noticing patterns.

Let’s ReviewGuided Practice

Find the product:

(-4) x 3 =

(-4) x (-3) =

-12

+12

Let’s ReviewExtension Activities

Without solving determine if the answer is positive or negative:

34(-23) -34(-23) -34(-23)(-29)

Let’s ReviewExtension Activities

Find the product of:

(-23) x (-34)

Let’s ReviewQuick Quiz

Find the product:

(-4) x 6 =

(-4) x (-2) =