GCF and LCM of 10 and 20
The greatest common factor and least common multiple of 10 and 20.
GCF of 10 and 20
10
LCM of 10 and 20
20
How it works
Break each number into its prime factors:
- 10 = 2 × 5
- 20 = 2² × 5
The GCF (10) multiplies the primes both share, at the lowest power each appears. The LCM (20) multiplies every prime that appears in either number, at the highest power — which is also 10 × 20 ÷ 10 = 20.
Try other numbers
Need a different pair? The LCM & GCF calculator computes the GCF and LCM for any two numbers.
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Frequently asked questions
What is the GCF of 10 and 20?+
The greatest common factor (GCF) of 10 and 20 is 10 — the largest number that divides both 10 and 20 with no remainder.
What is the LCM of 10 and 20?+
The least common multiple (LCM) of 10 and 20 is 20 — the smallest number that both 10 and 20 divide into. It equals 10 × 20 ÷ GCF = 200 ÷ 10 = 20.