Properties and Mental Computation p. 80

Math talk What are some math properties that we use? Why do you think we have them? Do you ever use them?

Commutative Property Commutative Property of addition Commutative Property of addition a+b = b+a a+b = b+a Commutative Property of multiplication Commutative Property of multiplication a x b = b x a a x b = b x a

Distributive Property This property has multiplication and either addition or subtraction This property has multiplication and either addition or subtraction a(b + c) = ab + ac a(b + c) = ab + ac a(b – c) = ab - ac a(b – c) = ab - ac

Associative Property Associative property of addition Associative property of addition (a+b)+c = a+(b+c) (a+b)+c = a+(b+c) Associative property of multiplication Associative property of multiplication (a x b) x c = a x (b x c) (a x b) x c = a x (b x c)

Please look at p. 84 Properties of equality Properties of equality Reflexive property a=a Reflexive property a=a Symmetric property a=b b=a Symmetric property a=b b=a Transitive property Transitive property a=b and b=c, then a=c a=b and b=c, then a=c

Please look at p. 86 #5 #6