1. Integers and Properties
Algebra I – Chapter 2
Integers and Properties

2. Integer Rules
Adding:
Different signs: Find the difference and keep the sign of the larger number
Ex: (-3) + (6) = (3)
Same signs: Add and keep the signs
Ex: (-3) + (-6) = (-9)

3. Integer Rules
Subtracting:
Add the Opposite

4. Integer Rules Multiplying and Dividing:
Different Signs: The answer is negative
Ex: (-6)(3) = (-18)
Same Sign: The answer is positive
Ex: (-4)(-5) = 20

5. Property Addition Multiplication
Commutative
a + b = b + a
Ab = ba
Associative
(a+b) + c = a + (b+c)
abc = cba
Identity
a + 0 = a
a (1) = a
Inverse
a + (-a) = 0
a (1/a) = 1
Distributive
a (b+c) = ab +ac and
a (b-c) = ab - ac

6. Property Symbols Examples
Reflexive
a = a
8 – n = 8 – n
Symmetric
If a = b then b = a
3x = 2 then 2 = 3x
Transitive
If a = b and b = c then a = c
If 2x = 8 and 8 = 5x – 3 then 2x = 5x - 3
Substitution
If a = b then a can be replaced by b and b can be replaced by a

7. Reflection:
What will the answer be when you multiply two numbers with the same signs?
What about when you divide two numbers with different signs?
When can associative property work?

8. Tonight’s Homework:
Page 641 – 642
(1-91 odd)