GCF and LCM of 5 and 20
The greatest common factor and least common multiple of 5 and 20.
GCF of 5 and 20
5
LCM of 5 and 20
20
How it works
Break each number into its prime factors:
- 5 = 5
- 20 = 2² × 5
The GCF (5) 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 5 × 20 ÷ 5 = 20.
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Frequently asked questions
What is the GCF of 5 and 20?+
The greatest common factor (GCF) of 5 and 20 is 5 — the largest number that divides both 5 and 20 with no remainder.
What is the LCM of 5 and 20?+
The least common multiple (LCM) of 5 and 20 is 20 — the smallest number that both 5 and 20 divide into. It equals 5 × 20 ÷ GCF = 100 ÷ 5 = 20.