LCM of 10 and 15
The least common multiple (LCM) of 10 and 15 is 30. Their greatest common factor (GCF) is 5.
Prime factorization method
Write each number as a product of primes: 10 = 2 × 5 and 15 = 3 × 5. The LCM takes every prime with its highest power, which gives 30. The GCF takes only the shared primes with their lowest power, which gives 5.
Check with the formula
For two numbers, LCM × GCF = a × b. Here 30 × 5 = 150, and 10 × 15 = 150, so the answer is correct.
Multiples of 10 and 15
Multiples of 10: 10, 20, 30, 40, 50, 60, 70, 80 … Multiples of 15: 15, 30, 45, 60, 75, 90, 105, 120 … The first number that appears in both lists is 30.
Popular calculations
Frequently asked questions
What is the LCM of 10 and 15?
The LCM of 10 and 15 is 30. It is the smallest positive number that both 10 and 15 divide into exactly.
What is the GCF of 10 and 15?
The greatest common factor of 10 and 15 is 5. It is the largest number that divides both without a remainder.
How do I find the LCM of 10 and 15 quickly?
Divide the product by the GCF: 10 × 15 = 150, and 150 ÷ 5 = 30.