LCM for 9 and 21

The first method to find LCM for numbers 9 and 21 is to find Greatest Common Factor (GCF) of these numbers. Here's the formula:

LCM = (Number1 × Number2) ÷ GCF

GCF of numbers 9 and 21 is 3, so

LCM = (9 × 21) ÷ 3

LCM = 189 ÷ 3

LCM = 63

The second method to find LCM for numbers 9 and 21 is to list out the common multiples for both nubmers and pick the first which matching:

Multiples of 9: 9, 18, 27, 36, 45, 54, 63, 72, 81

Multiples of 21: 21, 42, 63, 84, 105

So the LCM for 9 and 21 is 63

Another method to find LCM for numbers 9 and 21 is to list all Prime Factors for both numbers and multiply the highest exponent prime factors: