LCM for 21 and 70

What's the Least Common Multiple (LCM) of 21 and 70?

Answer: LCM of 21 and 70 is 210

(Two hundred ten)

Finding LCM for 21 and 70 using GCF's of these numbers

The first method to find LCM for numbers 21 and 70 is to find Greatest Common Factor (GCF) of these numbers. Here's the formula:

LCM = (Number1 × Number2) ÷ GCF

GCF of numbers 21 and 70 is 7, so

LCM = (21 × 70) ÷ 7

LCM = 1470 ÷ 7

LCM = 210

Finding LCM for 21 and 70 by Listing Multiples

The second method to find LCM for numbers 21 and 70 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

Multiples of 70: 70, 140, 210, 280, 350

So the LCM for 21 and 70 is 210

Finding LCM for 21 and 70 by Prime Factorization

Another method to find LCM for numbers 21 and 70 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 70: 2, 5, 7 (exponent form: 21, 51, 71)

31 × 71 × 21 × 51 = 210

See Also

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 70? (The answer is: 210). Select the first number (e.g. '21') and the second number (e.g. '70'). 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

LCM Table

Number 1Number 2LCM
670210
77070
870280
970630
107070
1170770
1270420
1370910
147070
1570210
1670560
17701190
1870630
19701330
2070
2170
2270770
23701610
2470840
2570
2670910
27701890
2870140
29702030
3070
31702170
32701120
33702310
34701190
3570

FAQ

What's the Least Common Multiple (LCM) of 21 and 70?

LCM of 21 and 70 is 210