GCF and LCM of 18 and 19
The greatest common factor and least common multiple of 18 and 19.
GCF of 18 and 19
1
LCM of 18 and 19
342
How it works
Break each number into its prime factors:
- 18 = 2 × 3²
- 19 = 19
The GCF (1) multiplies the primes both share, at the lowest power each appears. The LCM (342) multiplies every prime that appears in either number, at the highest power — which is also 18 × 19 ÷ 1 = 342.
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Frequently asked questions
What is the GCF of 18 and 19?+
The greatest common factor (GCF) of 18 and 19 is 1 — the largest number that divides both 18 and 19 with no remainder.
What is the LCM of 18 and 19?+
The least common multiple (LCM) of 18 and 19 is 342 — the smallest number that both 18 and 19 divide into. It equals 18 × 19 ÷ GCF = 342 ÷ 1 = 342.