__Greatest Common Factor__

Factors are the numbers that are multiplied to get an answer.

__First__: List the factors for each number given.

__Second__: Cross out all factors that are not common among all numbers.

__Third__: Circle the biggest factor that all numbers share.

Example:

__18__ __24__

1 X 18 1 X 24

2 X 9 2 X 12

3 X 6 3 X 8

4 X 6

1,2,3,6,~~9,18~~ 1,2,3,~~4~~,6,~~8,12,24~~

Common Factors: 1,2,3,6

Greatest Common Factor: 6

__Least Common Multiple__

Multiples are the products that you get when you multiply a number.

For example: The multiples of 3 are: 3, 6, 9, 12, 15, 18, 21, 24....

To find the least common multiple for given numbers:

__First__: List the multiples for each number given

__Then: __Find the * first* number that they both share.

Example:

4: 4, 8, 12, 16, **20**, 24, 28, 32

5: 5, 10, 15, **20**, 25, 30, 35

The least common multiple for 4 & 5 is 20.