Page 68 - Math Course 2 (Book 1)

Commutative and Associative Properties

Use Multiplication Properties Use Multiplication Properties

Evaluate 3 • 5 • 3 • 4.
Example A. 45

B. 36
Evaluate 2 • 8 • 5 • 7 using properties of numbers. C. 15
Name the property used in each step. D. 180

You can rearrange and group the factors to make Answer
mental calculations easier.

2 • 8 • 5 • 7 = 2 • 5 • 8 • 7 Commutative (×)

= (2 • 5) • (8 • 7) Associative (×)
MO. 2 - L5b
= 10 • 56 Multiply mentally.
Use the Commutative and
= 560 Multiply mentally.
Associative Property

Answer 560
Let’s Begin

Your Turn!
Write and Simplify an Expression
Use Addition Properties

The distance from Five Points to Garnett is 0.4
mile. From Garnett, West End is 1.5 miles. From Example
West End, Oakland City is 1.5 miles. Write an
expression to f nd the distance from Five Points to Use the expression three times the sum of 3x and
Oakland City, then write an expression to f nd the 2y added to f ve times the sum of x and 4y. Write an
distance from Oakland City to Five Points.
algebraic expression for the verbal expression.
Words three times f ve times
A. Five Points to Oakland City: 3(1.5) Oakland City the sum of the sum
to Five Points: 1.5(3) 3x and 2y added to of x and 4y
B. Five Points to Oakland City: 0.4 + 1.5 + 1.5 Variable Let x and y represent the numbers.
Oakland City to Five Points: 1.5 + 1.5 + 0.4

C. Five Points to Oakland City:0.4 + 0.4 + 1.5 Equation 3(3x + 2y) + 5(x + 4y)
Oakland City to Five Points:1.5 + 0.4 + 0.4

D. Five Points to Oakland City: 3(0.4) Oakland City Answer 3(3x + 2y) + 5(x + 4y)
to Five Points: 0.4(3)

Answer

60