Math Dictionary / Greatest Common Factor

Greatest Common Factor

The greatest common factor is the largest factor shared by two or more numbers.

Number SystemGrade 5Grade 6Grade 7Grade 8GED

What it means

It is often used to simplify fractions or factor expressions.

Also called: GCF

Examples

GCF of 12 and 18 is 6
GCF of 8 and 20 is 4
Use common factors to simplify fractions

Common mistake

The greatest common factor is a factor, not a multiple.

Try one

Question: What is the GCF of 10 and 15?

Show answer

5.

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