What is the LCM of 42 and 40?
The LCM of 42 and 40 is 840.
Steps to find LCM
- Find the prime factorization of 42
42 = 2 × 3 × 7 - Find the prime factorization of 40
40 = 2 × 2 × 2 × 5 - Multiply each factor the greater number of times it occurs in steps i) or ii) above to find the LCM:
LCM = 2 × 2 × 2 × 3 × 5 × 7 - LCM = 840
MathStep (Works offline)
Download our mobile app and learn how to find LCM of upto four numbers in your own time:
Android and iPhone/ iPad
Find least common multiple (LCM) of: 84 & 80 21 & 20 126 & 120 210 & 200 294 & 280 84 & 40 42 & 80 126 & 40 42 & 120 210 & 40 42 & 200 294 & 40 42 & 280
LCM Calculator
Enter two numbers separate by comma. To find least common multiple (LCM) of more than two numbers, click here.