GCF and LCM of 12 and 15
The greatest common factor and least common multiple of 12 and 15.
GCF of 12 and 15
3
LCM of 12 and 15
60
How it works
Break each number into its prime factors:
- 12 = 2² × 3
- 15 = 3 × 5
The GCF (3) 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 12 × 15 ÷ 3 = 60.
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Frequently asked questions
What is the GCF of 12 and 15?+
The greatest common factor (GCF) of 12 and 15 is 3 — the largest number that divides both 12 and 15 with no remainder.
What is the LCM of 12 and 15?+
The least common multiple (LCM) of 12 and 15 is 60 — the smallest number that both 12 and 15 divide into. It equals 12 × 15 ÷ GCF = 180 ÷ 3 = 60.