LCM for 21 and 70
What's the Least Common Multiple (LCM) of 21 and 70?
(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
Related Calculations
See Also
- Greatest Common Factor - Find the Greatest Common Factor (GCF) of two numbers
<a href="https://calculat.io/en/number/least-common-multiple-lcm-of/21--70">What is the LCM of 21 and 70? - Calculatio</a>
LCM Table
About "Least Common Multiple" Calculator
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