GCF and LCM of 5 and 15
The greatest common factor and least common multiple of 5 and 15.
GCF of 5 and 15
5
LCM of 5 and 15
15
How it works
Break each number into its prime factors:
- 5 = 5
- 15 = 3 × 5
The GCF (5) multiplies the primes both share, at the lowest power each appears. The LCM (15) multiplies every prime that appears in either number, at the highest power — which is also 5 × 15 ÷ 5 = 15.
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Frequently asked questions
What is the GCF of 5 and 15?+
The greatest common factor (GCF) of 5 and 15 is 5 — the largest number that divides both 5 and 15 with no remainder.
What is the LCM of 5 and 15?+
The least common multiple (LCM) of 5 and 15 is 15 — the smallest number that both 5 and 15 divide into. It equals 5 × 15 ÷ GCF = 75 ÷ 5 = 15.