LCM for 1, 2 and 3

"Least Common Multiple of 3 Numbers" Calculator

What's the Least Common Multiple (LCM) of 1, 2 and 3?

Answer

LCM of 1, 2 and 3 is

(Six)

6 is the smallest positive integer that 1, 2 and 3 all divide without a remainder — every other common multiple of the three is a multiple of it.

Finding the LCM of 1, 2 and 3 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:

1 has no prime factors — 1 is neither prime nor composite, and it never changes an LCM

All Prime Factors of 2: 2 (exponent form: 2)

All Prime Factors of 3: 3 (exponent form: 3)

Prime factor	1	2	3	Highest power
2	—	2	—	2
3	—	—	3	3

LCM = 2 × 3 = 6

Checking the LCM of 1, 2 and 3 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(1, 2) = (1 × 2) ÷ 1 = 2 ÷ 1 = 2

LCM(2, 3) = (2 × 3) ÷ 1 = 6 ÷ 1 = 6

LCM(1, 2, 3) = 6

The pairs may be taken in any order — 2 and 3 first, then 1 — and the answer is the same 6. That is exactly why the two routes on this page agree.

Related Calculations

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 1, 2 and 3? (The answer is: 6). Enter the first number (e.g. '1'), the second (e.g. '2') and the third (e.g. '3'), 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

LCM Table

Number 1	Number 2	Number 3	LCM
1	1	2	2
1	2	2	2
1	2	3	6
1	2	4	4
1	2	5	10
1	2	6	6
1	2	7	14
1	2	8	8
1	2	9	18
1	2	10	10
1	2	11	22
1	2	12	12
1	2	13	26
1	2	14	14
1	2	15	30
1	2	16	16
1	2	17	34
1	2	18	18
1	2	19	38
1	2	20	20
1	2	21	42
1	2	22	22
1	2	23	46
1	2	24	24
1	2	25	50
1	2	26	26
1	2	27	54
1	2	28	28
1	2	29	58
1	2	30	30

FAQ

What's the Least Common Multiple (LCM) of 1, 2 and 3?

LCM of 1, 2 and 3 is 6

How to find the LCM of 1, 2 and 3 by prime factorization?

Take every prime that appears in 1, 2 and 3 to the highest power it reaches in any one of them and multiply: 2 × 3 = 6.

Can you get the LCM of 1, 2 and 3 two numbers at a time?

Yes, and it is the check this page prints. The LCM of 1 and 2 is 2, and the LCM of 2 and 3 is 6 — the same answer, because the least common multiple is associative and does not depend on the order of the three numbers.

Is 6 divisible by 1, 2 and 3?

Yes, and by definition it is the smallest positive integer that is: 6 ÷ 1, 6 ÷ 2 and 6 ÷ 3 all come out whole. Any other common multiple of 1, 2 and 3 is a multiple of 6.

LCM for 1, 2 and 3

What's the Least Common Multiple (LCM) of 1, 2 and 3?

Finding the LCM of 1, 2 and 3 by Prime Factorization

Checking the LCM of 1, 2 and 3 Two Numbers at a Time

Related Calculations

See Also

About "Least Common Multiple of 3 Numbers" Calculator

LCM Table

FAQ

What's the Least Common Multiple (LCM) of 1, 2 and 3?

How to find the LCM of 1, 2 and 3 by prime factorization?

Can you get the LCM of 1, 2 and 3 two numbers at a time?

Is 6 divisible by 1, 2 and 3?

See Also

Number 1	Number 2	Number 3	LCM
1	1	2	2
1	2	2	2
1	2	3	6
1	2	4	4
1	2	5	10
1	2	6	6
1	2	7	14
1	2	8	8
1	2	9	18
1	2	10	10
1	2	11	22
1	2	12	12
1	2	13	26
1	2	14	14
1	2	15	30
1	2	16	16
1	2	17	34
1	2	18	18
1	2	19	38
1	2	20	20
1	2	21	42
1	2	22	22
1	2	23	46
1	2	24	24
1	2	25	50
1	2	26	26
1	2	27	54
1	2	28	28
1	2	29	58
1	2	30	30

Number 1	Number 2	Number 3	LCM
1	1	2	2
1	2	2	2
1	2	3	6
1	2	4	4
1	2	5	10
1	2	6	6
1	2	7	14
1	2	8	8
1	2	9	18
1	2	10	10
1	2	11	22
1	2	12	12
1	2	13	26
1	2	14	14
1	2	15	30
1	2	16	16
1	2	17	34
1	2	18	18
1	2	19	38
1	2	20	20
1	2	21	42
1	2	22	22
1	2	23	46
1	2	24	24
1	2	25	50
1	2	26	26
1	2	27	54
1	2	28	28
1	2	29	58
1	2	30	30

Number 1	Number 2	Number 3	LCM
1	1	2	2
1	2	2	2
1	2	3	6
1	2	4	4
1	2	5	10
1	2	6	6
1	2	7	14
1	2	8	8
1	2	9	18
1	2	10	10
1	2	11	22
1	2	12	12
1	2	13	26
1	2	14	14
1	2	15	30
1	2	16	16
1	2	17	34
1	2	18	18
1	2	19	38
1	2	20	20
1	2	21	42
1	2	22	22
1	2	23	46
1	2	24	24
1	2	25	50
1	2	26	26
1	2	27	54
1	2	28	28
1	2	29	58
1	2	30	30