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LCM Calculator

Find the Least Common Multiple (LCM) of two or more numbers. Free online LCM calculator.

LCM Calculator

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LCM

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LCM (Least Common Multiple) — Formula & Examples

The Least Common Multiple (LCM) of two or more numbers is the smallest positive integer that is divisible by all of them without a remainder. LCM is used to add or subtract fractions, find common scheduling intervals, and solve problems involving repeating events.

Methods to find LCM:
1. Prime Factorization: Find prime factors of each number, take highest power of each prime, multiply.
2. Division Method: Divide all numbers by common primes until all become 1, multiply all divisors.
3. GCF Method: LCM(a, b) = (a × b) ÷ GCF(a, b)

Numbers	LCM	How
4, 6	12	4=2², 6=2×3 → LCM=2²×3=12
8, 12	24	8=2³, 12=2²×3 → LCM=2³×3=24
5, 7	35	Co-prime: 5×7=35
6, 10, 15	30	2×3×5=30
12, 18, 24	72	2³×3²=72

What is the LCM of 12 and 18?

LCM(12,18): 12=2²×3, 18=2×3². LCM = 2²×3² = 4×9 = 36. Check: 36÷12=3 ✓, 36÷18=2 ✓.

How is LCM used to add fractions?

To add 1/4 + 1/6, find LCM(4,6)=12. Convert: 3/12 + 2/12 = 5/12. The LCM becomes the common denominator.

What is the difference between LCM and GCF?

LCM (Least Common Multiple) is the smallest number divisible by all given numbers. GCF (Greatest Common Factor / HCF) is the largest number that divides all given numbers. For 12 and 18: LCM=36, GCF=6. LCM × GCF = product of numbers: 36×6 = 12×18 = 216 ✓.