can you multiply these numbers mentally?

Can you multiply these numbers mentally?

x ( x 14)

How can you make a multiplication problem easier?

In this lesson you will learn to rewrite multiplication problems with rational numbers by using

the associative property of multiplication.

Let’s ReviewLet’s Review

Order of Operations1. Grouping Symbols2. Exponents3. Multiplication/Division worked left to

right4. Add/Subtract worked left to right

Let’s ReviewLet’s Review

Associative Property of multiplication3 x 4 x 5 =

12 x 5 =3 x 4 x 53 x 20

60 = 60(a x b) x c = a x (b x c)

Let’s ReviewA Common Mistake

Order of Operations

(3 + 4) x 5 = 3 + (4 x 5)35 ≠ 60

Let’s ReviewCore Lesson

x ( x 14) =

( x ) x 14 =1

11

2 x 14 = 7

Let’s ReviewCore Lesson

x (- x 25) =

( x -) x 25 =1

11

4 x -25 = - = -6 = -6.25

In this lesson you have learned to rewrite multiplication problems with rational numbers by using the associative property of

multiplication.

Let’s ReviewGuided Practice

Rewrite the multiplication the problem using the associative property and then solve:

- x ( x 10) =

(- x ) x 10 = 5

Let’s ReviewExtension Activities

Rewrite the multiplication using the associative property and solve:

(24 ÷ ) ÷ x x x

Let’s ReviewQuick Quiz

Rewrite the multiplication the problem using the associative property and then solve:

- x ( x 12) = (-20 x ) x =