Math PicnicFree printable practice

Least common multiple worksheets

The least common multiple is the smallest number that two values both divide into — the tool for adding fractions with unlike denominators. These free printable worksheets ask a child to find the LCM of a set of numbers, listed one set per line.

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Ready for harder? GCF & LCM puzzles — the GCF and the LCM are given and the two numbers are not.

Least common multiple
Least common multiple worksheet — 2 or 3 numbers, free printable with answer key

The answer key prints on a separate page.

What's on this sheet

Each set is built to share a common factor, so the least common multiple is genuinely smaller than the product — the practice trains a child to divide out the common factor rather than just multiply the numbers together. Answers are kept to a sensible size for grades five and six so the arithmetic stays reasonable while the idea comes into focus. Choose two numbers or three, and set the range with the level control.

Why this sheet works

Like the GCF sheet, the instruction is stated once at the top and each row is compact — 4, 6 → LCM = __ — so a whole page reads cleanly instead of repeating one sentence. The answer key prints the least common multiple for every set on a separate page.

How this one works

One question from this sheet, worked through a step at a time.

LCM of 10 and 25

10:1020304050
10:1020304050
25:2550
10:1020304050
25:2550
10:1020304050
25:2550
LCM=50
  1. Count up in 10s.
  2. Now count up in 25s.
  3. 50 turns up in every list — it is the first number all of them reach.
  4. Nothing smaller is in all of them, so 50 is the least common multiple.

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