The factors of a number are all the numbers that can divide the number without leaving a remainder. These include the number itself and the number 1.
The lowest factor of a number is the number 1, and the highest factor of a number is the number itself.
So what are common factors of a number?
What if you are asked to find the common factors of the numbers 6 and 12?
First, list all the factors of each number:
Factors of 6: 1, 2, 3 and 6.
Factors of 12: 1, 2, 3, 4, 6 and 12.
The common factors of a given set of numbers are the factors which both share.
For example, if we look at the factors of 6 and 12 above, we will see that both 6 and 12 share the factors: 1,2, 3 and 6.
Therefore the common factors of the numbers 3 and 6 are 1,2,3 and 6.
What do you think is the lowest common factor of the numbers 6 and 12?
What is the highest common factor of the two given numbers?