Factors
math/learn/factors/
Basic Factors
Factors are two numbers that are multiplied to make the number. For example, 1, 2, 3, 4, 6, 8, 12 and 24 are factors of 24. This is because 1×24, 2×12, 3×8 and 4×6 all multiply to give 24. As you can see, divisibility is a good skill to learn and you may want to visit the prime factors page. You write out the factors in numerical order. For 36, you would write 1, 2, 3, 4, 6, 9, 12, 18, 36. These numbers are factors of 36.
Common Factors
To find the common factors of 36 and 42, find the factors of each number.
Factors of 36: 1, 2, 3, 4, 6, 9, 12, 18, 36.
Factors of 42: 1, 2, 3, 6, 7, 14, 21, 42.
1, 2, 3 and 6 are common factors of 36 and 42.
Greatest Common Factors (GCF)
The greatest common factor is the common factor with the greatest numerical value. In the case above, it would be 6. I write it out like this: GCF6.
Prime and Composite Numbers
A prime number is a number that has ONLY 2 factors: 1, and the number itself. 29 is a perfect example. Its factors are 1 and 29. Can you think of any other prime numbers?
A composite number is simply, a number that has more than two factors. That's all.
