GCF and LCM of 5 and 9
The greatest common factor and least common multiple of 5 and 9.
GCF of 5 and 9
1
LCM of 5 and 9
45
How it works
Break each number into its prime factors:
- 5 = 5
- 9 = 3²
The GCF (1) multiplies the primes both share, at the lowest power each appears. The LCM (45) multiplies every prime that appears in either number, at the highest power — which is also 5 × 9 ÷ 1 = 45.
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Frequently asked questions
What is the GCF of 5 and 9?+
The greatest common factor (GCF) of 5 and 9 is 1 — the largest number that divides both 5 and 9 with no remainder.
What is the LCM of 5 and 9?+
The least common multiple (LCM) of 5 and 9 is 45 — the smallest number that both 5 and 9 divide into. It equals 5 × 9 ÷ GCF = 45 ÷ 1 = 45.