LCM for 28 and 105

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What's the Least Common Multiple (LCM) of 28 and 105?

Answer

LCM of 28 and 105 is
420

(Four hundred twenty)

Finding LCM for 28 and 105 using GCF of these numbers

The first method to find LCM for numbers 28 and 105 is to find Greatest Common Factor (GCF) of these numbers. Here's the formula:

LCM = (Number1 × Number2) ÷ GCF

GCF of numbers 28 and 105 is 7, so

LCM = (28 × 105) ÷ 7

LCM = 2,940 ÷ 7

LCM = 420

Finding LCM for 28 and 105 by Listing Multiples

The second method to find LCM for numbers 28 and 105 is to list out the common multiples for both numbers and pick the first one that matches:

Multiples of 28: 28, 56, 84, 112, 140, 168, 196, 224, 252, 280, 308, 336, 364, 392, 420, 448, 476

Multiples of 105: 105, 210, 315, 420, 525, 630

So the LCM for 28 and 105 is 420

Finding LCM for 28 and 105 by Prime Factorization

Another method to find LCM for numbers 28 and 105 is to list all Prime Factors for both numbers and multiply the highest exponent prime factors:

All Prime Factors of 28: 2, 2, 7 (exponent form: 22, 71)

All Prime Factors of 105: 3, 5, 7 (exponent form: 31, 51, 71)

22 × 71 × 31 × 51 = 420

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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 28 and 105? (The answer is: 420). Select the first number (e.g. '28') and the second number (e.g. '105'). 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
"Least Common Multiple" Calculator
Least Common Multiple of
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LCM Table

Number 1Number 2LCM
2830420
2831868
2832224
2834476
2835140
2836252
2838532
28391,092
2840280
28411,148
284284
28431,204
28451,260
2848336
2849196
2850700
28511,428
2852364
2854756
285656
28571,596
2858812
28591,652
2860420
2863252
2870140
2872504
288484
2898196
28105420

FAQ

What's the Least Common Multiple (LCM) of 28 and 105?

LCM of 28 and 105 is 420

How to find the LCM of 28 and 105 using prime factorization?

To find the LCM of 28 and 105, find all prime factors of both numbers, then multiply the highest power of each prime factor. The result is 420.

What is the difference between LCM and GCF?

LCM (Least Common Multiple) is the smallest number divisible by both numbers, while GCF (Greatest Common Factor) is the largest number that divides both. For 28 and 105: LCM = 420, GCF = 7.

See Also