What is the LCM of 21 and 72?

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What's the Least Common Multiple (LCM) of 21 and 72?

Answer: LCM of 21 and 72 is 504

(Five hundred four)

Finding LCM for 21 and 72 using GCF's of these numbers

The first method to find LCM for numbers 21 and 72 is to find Greatest Common Factor (GCF) of these numbers. Here's the formula:

LCM = (Number1 × Number2) ÷ GCF

GCF of numbers 21 and 72 is 3, so

LCM = (21 × 72) ÷ 3

LCM = 1512 ÷ 3

LCM = 504

Finding LCM for 21 and 72 by Listing Multiples

The second method to find LCM for numbers 21 and 72 is to list out the common multiples for both nubmers and pick the first which matching:

Multiples of 21: 21, 42, 63, 84, 105, 126, 147, 168, 189, 210, 231, 252, 273, 294, 315, 336, 357, 378, 399, 420, 441, 462, 483, 504, 525, 546

Multiples of 72: 72, 144, 216, 288, 360, 432, 504, 576, 648

So the LCM for 21 and 72 is 504

Finding LCM for 21 and 72 by Prime Factorization

Another method to find LCM for numbers 21 and 72 is to list all Prime Factors for both numbers and multiply the highest exponent prime factors:

All Prime Factors of 21: 3, 7 (exponent form: 3¹, 7¹)

All Prime Factors of 72: 2, 2, 2, 3, 3 (exponent form: 2³, 3²)

3² × 7¹ × 2³ = 504

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About "Least Common Multiple" Calculator

This calculator will help you find the Least Common Multiple (LCM) of two numbers. For example, it can help you find out what's the Least Common Multiple (LCM) of 21 and 72? (The answer is: 504). Select the first number (e.g. '21') and the second number (e.g. '72'). After that hit the 'Calculate' button.

Least Common Multiple (LCM) also known as the Lowest Common Multiple or Smallest Common Multiple of 2 numbers - it is the smallest positive integer that is divisible by both numbers

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LCM Table

Number 1	Number 2	LCM
6	72	72
7	72	504
8	72	72
9	72	72
10	72	360
11	72	792
12	72	72
13	72	936
14	72	504
15	72	360
16	72	144
17	72	1224
18	72	72
19	72	1368
20	72	360
21	72	504
22	72	792
23	72	1656
24	72	72
25	72	1800
26	72	936
27	72	216
28	72	504
29	72	2088
30	72	360
31	72	2232
32	72	288
33	72	792
34	72	1224
35	72	2520

LCM for 21 and 72

"Least Common Multiple" Calculator

What's the Least Common Multiple (LCM) of 21 and 72?

Finding LCM for 21 and 72 using GCF's of these numbers

Finding LCM for 21 and 72 by Listing Multiples

Finding LCM for 21 and 72 by Prime Factorization

Related Calculations

See Also

About "Least Common Multiple" Calculator

"Least Common Multiple" Calculator

LCM Table

FAQ

What's the Least Common Multiple (LCM) of 21 and 72?

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