Page 105 - Math Course 1 (Book 1)

Properties of Addition and Multiplication

Name the property shown by the statement. MO. 3 - L3b
12 + 9 = 9 + 12
Simplifying Algebraic
A. Commutative Property of Addition
B. Associative Property of Addition Expressions
C. Additive Identity
D. Distributive Property
Vocabulary A-Z
Answer
Let us learn some vocabulary

Simplify

to write algebraic expressions in a simpler form.
Mental Math

Find 4 8 25 mentally. (k + 2) + 7
(k + 2) + 7 = k + (2 + 7)
A. 200
B. 600 = k+ 9
C. 800
D. 1250
Let’s Begin
Answer

Simplify Algebraic Expressions

Examples

Find a Counterexample Simplify 5 (3 r).

State whether the following conjecture is true or 5 (3 r) = (5 3)r Associative Property of
false. If false, provide a counterexample. Multiplication.
Subtraction of whole number is commutative.
= 15r Substitution Property of
Equality; 5 3 = 15
A. true
B. false, 7 – 4 = 7 – 4
Answer 15r
C. false, 7 – 4 ≠ 4 – 7
D. false, (7 – 4) – 2 ≠ 7 – (4 – 2)
Simplify 12 + (x + 18).
Answer
12 + (x + 18) = 12 + (18 + x) Commutative
Property of Addition

= (12 + 18) + x Associative Property
of Addition

= 30 + x Substitution Property
of Equality;
12 + 18 = 30

Answer 30 + x

97