# Finding the LCM Least Common Multiple The LCM

- Slides: 9

Finding the LCM Least Common Multiple The LCM is the Lowest Number that is a Multiple of Both Numbers. Ex. The LCM of 12 & 9 is 36 since both 12 & 9 divide evenly into 36. Hint: Think of Common Denominators in Fractions. A common denominator is the LCM of the denominators.

Find LCM of 45 & 75 Finding Least Common Multiple

Finding Least Common Multiple Find LCM of 45 & 75 45 5 75 9 5 • 3 25 3 5 • 3 1. Complete Factor Tree for both numbers.

Finding Least Common Multiple Find LCM of 45 & 75 45 5 75 9 5 • 3 THE COMMON FACTORS ARE 5 & 3 25 3 5 • 3 1. 2. Complete Factor Tree for both numbers. Identify Common Factors.

Finding Least Common Multiple Find LCM of 45 & 75 45 5 75 9 5 • 3 25 3 1. 2. 3. Complete Factor Tree for both numbers. Identify Common Factors. Multiply Common Factors with ALL OTHER FACTORS 5 • 3 THE COMMON FACTORS ARE 5 & 3 OTHER FACTORS LCM = CF’s • ALL OTHER FACTORS LCM = 5 • 3 • 5 • 3 = 225

Find LCM of 225, 10 & 66 Finding the LCM Least Common Multiple (FOR 3 NUMBERS)

Find LCM of 225, 10 & 66 225 1. 10 5 66 45 5 Finding the LCM Least Common Multiple (FOR 3 NUMBERS) 5 • 2 9 5 • 3 • 3 11 6 11 • 3 • 2 Complete Factor Tree for all numbers.

Find LCM of 225, 10 & 66 225 1. 10 5 66 45 5 Finding the LCM Least Common Multiple (FOR 3 NUMBERS) 5 • 2 9 5 • 3 • 3 11 6 11 • 3 • 2 THE COMMON FACTORS ARE 2, 5 & 3 2. Complete Factor Tree for all numbers. Identify Common Factors OF ANY 2 #’S.

Find LCM of 225, 10 & 66 225 1. 10 5 66 45 5 Finding the LCM Least Common Multiple (FOR 3 NUMBERS) 5 • 2 9 5 • 3 • 3 2. 3. 11 6 Complete Factor Tree for all numbers. Identify Common Factors OF ANY 2 #’S. Multiply Common Factors with ALL OTHER FACTORS 11 • 3 • 2 THE COMMON FACTORS ARE 2, 5 & 3 LCM=2 • 5 • 3 • 11=4950 OTHER FACTORS