Integers and Properties Algebra I – Chapter 2 Integers and Properties

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)

Integer Rules Subtracting: Add the Opposite

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

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

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

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?

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