LCM for 6, 15 and 18

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What's the Least Common Multiple (LCM) of 6, 15 and 18?

Answer

LCM of 6, 15 and 18 is
90

First common multiples: 90, 180, 270, …

90 is divisible by all three: 90 ÷ 6 = 15, 90 ÷ 15 = 6, 90 ÷ 18 = 5 — and 15, 6 and 5 have no factor but 1 common to all of them, so no smaller number is. As a common denominator: multiply the top and bottom of x/6 by 15 and of y/15 by 6 and of z/18 by 5.

6 = 2 × 3

15 = 3 × 5

18 = 2 × 32

Prime61518Highest power
22—22
3333232
5—5—5

— = power 0: the prime is not a factor of this number; the LCM takes it from the number that has it.

LCM = 2 × 32 × 5 = 90

See Also

LCM Table

1st2nd3rdLCM
361530
461560
561530
661530
6715210
6815120
691590
6101530
61115330
6121560
61315390
61415210
6151530
61516240
61517510
6151890
61519570
6152060
61521210
61522330
61523690
61524120
61525150
61526390
61527270
61528420
61529870
6153030
61531930
61532480

FAQ

What's the Least Common Multiple (LCM) of 6, 15 and 18?

LCM of 6, 15 and 18 is 90

How to find the LCM of 6, 15 and 18 by prime factorization?

Take every prime that appears in 6, 15 and 18 to the highest power it reaches in any one of them and multiply: 2 × 3² × 5 = 90.

Can you get the LCM of 6, 15 and 18 two numbers at a time?

Yes. The LCM of 6 and 15 is 30, and the LCM of 30 and 18 is 90 — the same answer, because the least common multiple is associative and does not depend on the order of the three numbers.

Is 90 divisible by 6, 15 and 18?

Yes, and by definition it is the smallest positive integer that is: 90 ÷ 6, 90 ÷ 15 and 90 ÷ 18 all come out whole. Any other common multiple of 6, 15 and 18 is a multiple of 90.