GCF and LCM of 20 and 30
The greatest common factor and least common multiple of 20 and 30.
GCF of 20 and 30
10
LCM of 20 and 30
60
How it works
Break each number into its prime factors:
- 20 = 2² × 5
- 30 = 2 × 3 × 5
The GCF (10) multiplies the primes both share, at the lowest power each appears. The LCM (60) multiplies every prime that appears in either number, at the highest power — which is also 20 × 30 ÷ 10 = 60.
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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 20 and 30?+
The greatest common factor (GCF) of 20 and 30 is 10 — the largest number that divides both 20 and 30 with no remainder.
What is the LCM of 20 and 30?+
The least common multiple (LCM) of 20 and 30 is 60 — the smallest number that both 20 and 30 divide into. It equals 20 × 30 ÷ GCF = 600 ÷ 10 = 60.