Page 103 - Math Course 1 (Book 1)

Properties of Addition and Multiplication

Mo. 3

Lesson 3

KEY CONCEPTS: Key Concept
1. Identify and use properties of addition
and multiplication.
2. Use properties of addition and multiplication to Commutative Property
simplify algebraic expressions.
of Addition
Words The order in which numbers are added
does not change the sum.
MO. 3 - L3a Symbols For any numbers a and b, a + b = b + a.

Identifying the Properties of Examples 2 + 3 = 3 + 2
Addition and Multiplication 5 = 5

Vocabulary A-Z Commutative Property

Let us learn some vocabulary
of Multiplication
Words The order in which numbers are
multiplied does not change the product.
Symbols For any numbers a and b, a b = b a.
Properties
Examples 2 3 = 3 2
in algebra, properties are statements that are true 6 = 6
for any numbers.

The expression 3 + 8 and 8 + 3 have the
same value, 11. So the property is a
a + b = b + a. Associative Property
of Addition

Words The way which number are grouped
Counterexample when added does not change the sum.
is an example that shows a conjecture is not true. Symbols For any numbers a, b and c,
(a + b) + c = a + (b + c).
Associative Property of Subtraction? Examples (5 + 8) + 2 = 5 + (8 + 2)
13 + 2 = 5 + 10
9 - (5 - 3) = (9 - 5) - 3 State the conjecture.
15 = 15
9 - 2 = 4 - 3 Simplify within the
parenthesis

7 = 1 Subtract. Associative Property
of Multiplication
Deductive Reasoning Words The way which number are grouped
when multiplied does not change the
using facts, properties, or rules to reach valid product.
conclusions.
Symbols For any numbers a, b and c,
A is true Asians are good at math (a b) c = a (b c).

A imples B Thais are Asian. Examples (4 6) 3 = 4 (6 3)
24 3 = 4 18
72 = 72
Therefore B is true Therefore, Thais are good
at math.

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