When we multiply a number by each non-zero whole number, we obtain a list known as the multiples of that number. When we do this for several numbers, we can compare those lists to look for a common multiple that has the lowest value. This is known as the least common multiple or LCM.

Test Objectives
• Demonstrate the ability to generate the multiples of a number
• Demonstrate the ability to find the LCM using the listing method
• Demonstrate the ability to find the LCM using the prime factorization of each number
LCM Practice Test:

#1:

Instructions: Find the LCM by listing the multiples of each number.

a) LCM(4, 10)

b) LCM(6, 21)

#2:

Instructions: Find the LCM.

a) LCM(15, 18)

b) LCM(14, 63)

#3:

Instructions: Find the LCM.

a) LCM(24, 81, 156)

#4:

Instructions: Find the LCM.

a) LCM(121, 165, 231)

#5:

Instructions: Find the LCM.

a) LCM(550, 150, 225)

Written Solutions:

#1:

Solutions:

a) LCM(4, 10) = 20

b) LCM(6, 21) = 42

#2:

Solutions:

a) LCM(15, 18) = 90

b) LCM(14, 63) = 126

#3:

Solutions:

a) LCM(24, 81, 156) = 8424

#4:

Solutions:

a) LCM(121, 165, 231) = 12,705

#5:

Solutions:

a) LCM(550, 150, 225) = 4950