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LCM of Two Numbers: Every Pair Worked Out

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LCM of two numbers: 10 pairs, each worked out six ways

The LCM of two numbers is the smallest number both divide into. Each page below gives it for one pair with the full working: listing multiples, prime factorization, ladder and division tables, the GCF formula and a Venn diagram. For any other numbers, use the LCM Calculator.

LCM of two numbers: every pair on this site

PairLCMGCFPage
4 and 6122LCM of 4 and 6
6 and 7421LCM of 6 and 7
6 and 8242LCM of 6 and 8
6 and 9183LCM of 6 and 9
6 and 10302LCM of 6 and 10
7 and 8561LCM of 7 and 8
7 and 9631LCM of 7 and 9
8 and 9721LCM of 8 and 9
8 and 12244LCM of 8 and 12
9 and 12363LCM of 9 and 12

How the pair pages work

Answer first

Each page states the LCM in its first sentence, then shows the GCF and the divisibility check.

Six methods, same answer

Listing multiples, prime factorization, the cake/ladder, the division method, the GCF formula and a Venn diagram all reach the same number; pick the one your class uses.

Open in the calculator

Every page has a link that loads its pair into the Least Multiple Calculator, so you can change a number and watch the working update.

Frequently asked questions

How do I find the LCM of two numbers?

Use LCM(a, b) = a × b ÷ GCF(a, b), or take every prime factor at its highest power. For 6 and 8: GCF = 2, so LCM = 6 × 8 ÷ 2 = 24. Each pair page below shows both routes.

Which pairs have their own page?

The 10 pairs people search for most, from LCM of 4 and 6 to LCM of 9 and 12; more are added every day. Every other pair is one click away in the calculator.

Is the LCM of two numbers ever smaller than one of them?

No. The LCM is at least as large as the larger number, and equals it when one number divides the other: LCM(4, 8) = 8.

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