GCF and LCM of 42 and 56
The greatest common factor and least common multiple of 42 and 56.
GCF of 42 and 56
14
LCM of 42 and 56
168
How it works
Break each number into its prime factors:
- 42 = 2 × 3 × 7
- 56 = 2³ × 7
The GCF (14) multiplies the primes both share, at the lowest power each appears. The LCM (168) multiplies every prime that appears in either number, at the highest power — which is also 42 × 56 ÷ 14 = 168.
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Frequently asked questions
What is the GCF of 42 and 56?+
The greatest common factor (GCF) of 42 and 56 is 14 — the largest number that divides both 42 and 56 with no remainder.
What is the LCM of 42 and 56?+
The least common multiple (LCM) of 42 and 56 is 168 — the smallest number that both 42 and 56 divide into. It equals 42 × 56 ÷ GCF = 2352 ÷ 14 = 168.