What is the LCM of 21 and 45?

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What's the Least Common Multiple (LCM) of 21 and 45?

Answer: LCM of 21 and 45 is 315

(Three hundred fifteen)

Finding LCM for 21 and 45 using GCF's of these numbers

The first method to find LCM for numbers 21 and 45 is to find Greatest Common Factor (GCF) of these numbers. Here's the formula:

LCM = (Number1 × Number2) ÷ GCF

GCF of numbers 21 and 45 is 3, so

LCM = (21 × 45) ÷ 3

LCM = 945 ÷ 3

LCM = 315

Finding LCM for 21 and 45 by Listing Multiples

The second method to find LCM for numbers 21 and 45 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

Multiples of 45: 45, 90, 135, 180, 225, 270, 315, 360, 405

So the LCM for 21 and 45 is 315

Finding LCM for 21 and 45 by Prime Factorization

Another method to find LCM for numbers 21 and 45 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 45: 3, 3, 5 (exponent form: 3², 5¹)

3² × 7¹ × 5¹ = 315

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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 45? (The answer is: 315). Select the first number (e.g. '21') and the second number (e.g. '45'). 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	45	90
7	45	315
8	45	360
9	45	45
10	45	90
11	45	495
12	45	180
13	45	585
14	45	630
15	45	45
16	45	720
17	45	765
18	45	90
19	45	855
20	45	180
21	45	315
22	45	990
23	45	1035
24	45	360
25	45	225
26	45	1170
27	45	135
28	45	1260
29	45	1305
30	45	90
31	45	1395
32	45	1440
33	45	495
34	45	1530
35	45	315

LCM for 21 and 45

"Least Common Multiple" Calculator

What's the Least Common Multiple (LCM) of 21 and 45?

Finding LCM for 21 and 45 using GCF's of these numbers

Finding LCM for 21 and 45 by Listing Multiples

Finding LCM for 21 and 45 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 45?

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