Math 251

Partition

has 78 stickers needs to give 13 to each kid

Missing Factor

If he started with 78 candies and gave
6 to each kid how many kids were there

repeated subtraction

Has 78 dollars needs to give money to 13 kids

Decomposing to make it friendly

4816/4
4000/4=1000
800/4= 200
16/4= 4
4816/4=1204

Multiplying:
A * B = C
-A * B = -C
A * -B = -C
-A * -B = C

Negative times a negative is positive
Positive times a negative is negative

Dividing:
A/B = C
-A/ B = -C
A/-B = -C
-A/-B = C

Negative and positive is always negative
A Negative and a negative are always positive

Scientific

384= 3x10^2 + 4 x 10^1 +6 x 10^0

can be used in ratio table, area models, and partial quotients

normal

348= 300 + 40 +8

writing out the hundreds then tens then ones place

Properties

Communitive:

A x B = B xA

Identity Property:

A x 1 = A

Distributive Property

A x (B+C) = (AxB) + (AxC)

Associative:

A x (BxC) = (AxB) x C

strategies

Traditional

12
x13

Partial Products

1x12= 12
2x12= 24
10x12=120

Ratio Table

Models

Tree/Combinations

Factoring out numbers and mulitpling smaller numbers can make mulltiplication easier. If the number was 48 the picture below is two ways you could factor it out
Jill has 4 pairs of pants with 6 different shirts how many combinations can she make?

Area Model/Array

using rows and columns to find how much is in a given area
Areas can be broken up and added together in order to simplify.
There are 4 rows of 9 chairs how many chairs are there?

Repeated Addtion

Multiplying is just like adding the same number multiple times. Ex: 5 X 3 is like adding 5 + 5 + 5 or 3 + 3 +3 +3 +3
John has 4 plates with 5 oreos; how many oreos does he have?