1. 2.1 Properties and Operations
Pre-Algebra
Unit 1

2. Properties
A property is something that is true for all situations.

3. Commutative Property of Addition
In a sum, you can add the numbers in any order.
A + B = B + A
Order doesn’t matter

4. Commutative Property of Multiplication
In a product, you can multiply the numbers in any order.
A x B = B x A
Order doesn’t matter

5. Associative Property of Addition
Changing the grouping of the numbers in a sum does not change the sum.
Associative Property  (a + b) + c = a + (b + c)
Example: (6 + 4) + 3 = 6 + (4 + 3)
Who’s hangin’ with who?

6. Associative Property of Multiplication
Changing the grouping of the numbers in a product does not change the product.
Associative Property  (a · b) · c = a · (b · c)
Example: (6 · 4) · 3 = 6 · (4 · 3)
Who’s hangin’ with who?

7. Identity Property of Addition
The sum of a number and zero (additive identity), is the number.
If you add 0 to any number, the number stays the same.

8. Identity Property of Multiplications
The Product of a number and one (multiplicative identity), is the number.
If you multiply any number times 1, the number stays the same.