Finding Least Common Denominators and Multiples

The video tutorial explains how to find the least common denominator (LCD) or lowest common multiple (LCM) when adding fractions. It starts by listing multiples of numbers to identify the first common multiple. The tutorial demonstrates this process with examples, showing how to add fractions once a common denominator is found. It also covers special cases where one number is the common denominator and explains how multiplying numbers can help find common multiples.

Why is it important to find the least common denominator when adding fractions?

• To ensure the fractions have the same numerator

• To make the fractions easier to multiply

• To make the fractions easier to subtract

• To ensure the fractions have the same denominator

What is the first step in finding the least common multiple of two numbers?

• Divide the numbers

• List the multiples of each number

• Subtract the numbers

• Add the numbers

What is the least common multiple of 4 and 6?

• 14

• 12

• 10

• 8

What is the least common multiple of 2 and 12?

• 12

• 6

• 10

• 8

What is the least common multiple of 5 and 10?

• 5

• 10

• 15

• 20

What is the least common multiple of 7 and 14?

• 7

• 21

• 14

• 28

What is the least common multiple of 8 and 16?

• 8

• 12

• 16

• 24

What is the least common multiple of 9 and 18?

• 9

• 18

• 27

• 36

What is the least common multiple of 10 and 20?

• 20

• 10

• 30

• 40

How do you add fractions once they have the same denominator?

• Add the denominators and keep the numerators the same

• Subtract the numerators and keep the denominator the same

• Add the numerators and keep the denominator the same

• Multiply the numerators and denominators