What is a Factor of a number?

Suppose one number divides a second number exactly then the first number is a factor of the second. For example 3 divides 12 into 4. We can say that 3 and 4 are factors of 12.

To know that 12 has order factors, let us look at the table in fig 1

This shows all number that make the statement a x b= 12 true to be the factor of 12.

Therefore, the set of factors of 12 is {1, 2, 3, 4, 6, and 12}. The set consist of 6 numbers.

Fig 2 shows the first ten counting numbers and their set of factors. Students have to study them cautiously.