Fraction Addition and Multiplication Concepts

This video tutorial explains how to add fractions with different denominators by finding a common denominator. It provides three examples: adding two-thirds and two-ninths, four-sevenths and one-third, and one-eighth and two-sixths. Each example demonstrates finding the lowest common multiple, adjusting numerators, and adding the fractions. The video concludes with an interactive exercise to identify mistakes in fraction addition.

Why is it necessary to find a common denominator when adding fractions?

• To convert fractions to decimals

• To ensure the fractions have the same base for addition

• To simplify the fractions

• To make the numerators equal

What is the lowest common multiple of 3 and 9?

• 3

• 6

• 12

• 9

In the first example, what do you multiply the numerator of two-thirds by to get the equivalent fraction with a denominator of 9?

• 2

• 3

• 4

• 5

What is the result of adding two-thirds and two-ninths?

• 9/9

• 8/9

• 10/9

• 7/9

What is the lowest common multiple of 7 and 3?

• 14

• 18

• 21

• 24

In the second example, what do you multiply the numerator of four-sevenths by to get the equivalent fraction with a denominator of 21?

• 4

• 5

• 2

• 3

What is the result of adding four-sevenths and one-third?

• 20/21

• 18/21

• 17/21

• 19/21

What is the lowest common multiple of 8 and 6?

• 16

• 18

• 20

• 24

In the third example, what do you multiply the numerator of one-eighth by to get the equivalent fraction with a denominator of 24?

• 2

• 3

• 5

• 4

What is the result of adding one-eighth and two-sixths?

• 11/24

• 10/24

• 12/24

• 9/24