Least common multiple of 7 and 21

21

Step-by-step explanation:

Since 7 x 3 is 21

And 21 x 1 is 21

21

Step-by-step explanation:

To find the least common multiple of 7 and 21, we need to break each number down to its prime factors

7 = 7

21 = 7*3

To find the least common multiple multiply each factor the greatest number of times it occurs in either number.

The LCM = 7*3

= 21