400
List the multiples of 4, up to 4x10.
List the multiples of 5, up to 5x10.
What multiples do 4 and 5 have in common? What is the least common multiple between 4 and 5?
What is 4, 8, 12, 16, 20, 24, 28, 32, 36, 40
5, 10, 15, 20, 25, 30, 35, 40, 45, 50
20, 40 are the common multiples and 20 is the least common multiple