multiplication terms multiplier: 4 multiplicand:3 product:12 factors: 4 and 3 are factors of 12...

Multiplication terms

1234

multiplier: 4multiplicand: 3product: 12factors: 4 and 3 are factors of 12multiple: 12 is a multiple of 4

12 is a multiple of 3

Multiplication Models

• Repeated addition

• Area

• Cartesian product

3333

a1

a2

a3

Figure 3.13

Units

• For addition and subtraction3 hours plus 5 miles

• For multiplication

8 miles per hour for 5 hours:how many miles?8 mi • 5 hr = 40 mi

hr

Multiplication

Properties

• Identity

• Zero

• Commutative

• Associative

Multiplication

Properties continued:

Distributive property--

combines multiplication and addition or subtraction

Class Notes--Vidoes

• In general, watch the videos, and try to notice:a) what is the child doing?b) mathematically, what is going on?c) mathematically, why is it correct or incorrect.

The area model and the standard multiplication algorithm

Figure 3.20

Figure 3.21

Figure 3.22

Expanded vs compacted

Expanded Compacted

Multiplication-the area model

• How could Jemea’s strategy be represented using the rectangular area model?

10 + 10 + 10 + 2

10

+

4

Understanding FOIL