2.4.notebook
2.4
January 26, 2016
Multiplication and Division
Definition of Multiplication
a
b=
Models of Multiplication
Repeated Addition
5x7 = 5 + 5 + 5 + 5 + 5 + 5 + 5 = 35
a.k.a.: "Skip Counting"
Rectangular Array
= 35
5x7 =
Multiplication Tree
5x2 =
= 10
Cartesian Product
If and
then ...but, what is that x thing? Some set operation??
Yes:
1
2.4.notebook
January 26, 2016
Area Model
Properties of Multiplication
Closure Property:
Commutative Property:
Associative Property:
Multiplicative Identity Property of One:
Multiplication by Zero Property:
Distributive Property:
Why have Distribution?
2
2.4.notebook
January 26, 2016
Definition of Division
means
Models of Division
Repeated Subtraction
Missing Factor
Partition
60 jellybeans
Why can't you divide by zero?
3