LCM for 5, 15 and 30

"Least Common Multiple of 3 Numbers" Calculator
Least Common Multiple of
,
and

What's the Least Common Multiple (LCM) of 5, 15 and 30?

Answer

LCM of 5, 15 and 30 is
30

(Thirty)

30 is the smallest positive integer that 5, 15 and 30 all divide without a remainder — every other common multiple of the three is a multiple of it.

Finding the LCM of 5, 15 and 30 by Prime Factorization

Split all three numbers into prime factors, then take every prime that shows up in at least one of them, each raised to the highest power it reaches there. Multiplying those highest powers gives the least common multiple:

All Prime Factors of 5: 5 (exponent form: 5)

All Prime Factors of 15: 3 × 5 (exponent form: 3 × 5)

All Prime Factors of 30: 2 × 3 × 5 (exponent form: 2 × 3 × 5)

Prime factor51530Highest power
2——22
3—333
55555

LCM = 2 × 3 × 5 = 30

Checking the LCM of 5, 15 and 30 Two Numbers at a Time

The least common multiple is associative, so three numbers can be handled as two pairs: first the LCM of the first two, then the LCM of that value and the third. Each pair goes through the two-number formula, which uses the greatest common divisor:

LCM(a, b) = (a × b) ÷ GCD(a, b)

LCM(5, 15) = (5 × 15) ÷ 5 = 75 ÷ 5 = 15

LCM(15, 30) = (15 × 30) ÷ 15 = 450 ÷ 15 = 30

LCM(5, 15, 30) = 30

The pairs may be taken in any order — 15 and 30 first, then 5 — and the answer is the same 30. That is exactly why the two routes on this page agree.

Related Calculations

See Also

About "Least Common Multiple of 3 Numbers" Calculator

This calculator finds the Least Common Multiple (LCM) of three numbers at once, without doing it in two passes. For example, it can help you find out what's the Least Common Multiple (LCM) of 5, 15 and 30? (The answer is: 30). Enter the first number (e.g. '5'), the second (e.g. '15') and the third (e.g. '30'), then hit the 'Calculate' button.
The Least Common Multiple of three numbers is the smallest positive integer that all three of them divide without a remainder
"Least Common Multiple of 3 Numbers" Calculator
Least Common Multiple of
,
and

LCM Table

Number 1Number 2Number 3LCM
5151515
51516240
51517255
5151890
51519285
5152060
51521105
51522330
51523345
51524120
5152575
51526390
51527135
51528420
51529435
5153030
51531465
51532480
51533165
51534510
51535105
51536180
51537555
51538570
51539195
51540120
51541615
51542210
51543645
51544660

FAQ

What's the Least Common Multiple (LCM) of 5, 15 and 30?

LCM of 5, 15 and 30 is 30

How to find the LCM of 5, 15 and 30 by prime factorization?

Take every prime that appears in 5, 15 and 30 to the highest power it reaches in any one of them and multiply: 2 × 3 × 5 = 30.

Can you get the LCM of 5, 15 and 30 two numbers at a time?

Yes, and it is the check this page prints. The LCM of 5 and 15 is 15, and the LCM of 15 and 30 is 30 — the same answer, because the least common multiple is associative and does not depend on the order of the three numbers.

Is 30 divisible by 5, 15 and 30?

Yes, and by definition it is the smallest positive integer that is: 30 ÷ 5, 30 ÷ 15 and 30 ÷ 30 all come out whole. Any other common multiple of 5, 15 and 30 is a multiple of 30.

See Also