Common factors and multiples
In a nutshell
A multiple is a number you get when you multiply a certain number by a whole number. A factor is a number that divides into a certain number exactly with no remainder. Multiples and factors can be shared between different numbers.
Common multiples
Common multiples are multiples which are the same between two or more numbers.
Example 1
What are all the common multiples of 6 and 9 between 1 and 50?
List all the multiples of 6 and 9 between 1 and 50.
Multiples of 6 | Multiples of 9 |
6 | 9 |
12 | 18 |
18 | 27 |
24 | 36 |
30 | 45 |
36 | |
42 | |
48 | |
Identify the common multiples in the table.
Common multiples of 6 and 9 are 18,36.
Note: There are an infinite number of common multiples between all numbers.
Common factors
Common factors are factors of two or more numbers which are the same.
Example 2
What are the common factors of 24 and 16?
Identify the factors of 24.
Factors of 24 are 1,2,3,4,6,8,12,24
Identify the factors of 16.
Factors of 16 are 1,2,4,8,16
Identify which factors are the same for 24 and 16.
Common factors of 16 and 24 are 1,2,4,8.
Note: By listing factors it is possible to find the highest common factor between numbers.