Practice: LCM & GCF – Math Fun for Kids

LCM & GCF

Find the LCM or GCF of two numbers (e.g. LCM of 4 and 6 = 12).

★ Choose Your Level:

Easy

(1-10)

Medium

(1-50)

Hard

(1-100)

Expert

(10-500)

☰ How Many Problems?

Quick

Normal

Challenge

Marathon

Did you know?

LCM is the smallest number that both numbers divide into.

GCF is the largest number that divides into both numbers.

LCM and GCF help with fractions and factors!

Understand LCM & GCF before you start

Read this if you're new to the topic—it will help you know what to do in each problem.

LCM (Least Common Multiple) is the smallest number that both numbers divide into. For 4 and 6, multiples of 4 are 4, 8, 12, 16… and of 6 are 6, 12, 18… So LCM is 12.

GCF (Greatest Common Factor) is the largest number that divides both. For 12 and 18, factors of 12 are 1,2,3,4,6,12 and of 18 are 1,2,3,6,9,18. So GCF is 6.

Examples

LCM of 4 and 6 = 12

GCF of 12 and 18 = 6