Adding and Subtracting Fractions with Unlike Denominators

Mr. Nerian teaches fifth graders how to add and subtract fractions with unlike denominators by finding equivalent fractions. The lesson covers identifying the lowest common multiple and creating equivalent fractions to simplify the process. Students are encouraged to apply these methods to both addition and subtraction of fractions.

Why can't you directly add fractions with different denominators?

• Because they are improper fractions.

• Because they are mixed numbers.

• Because they represent different parts of a whole.

• Because they are already in simplest form.

What is the first step in adding fractions with unlike denominators?

• Find the lowest common multiple.

• Find the greatest common divisor.

• Convert them to mixed numbers.

• Simplify the fractions.

What is the lowest common multiple (LCM) of 2 and 3?

• 12

• 6

• 3

• 2

How do you create an equivalent fraction for 1/2 with a denominator of 6?

• Multiply the numerator and denominator by 2.

• Multiply the numerator and denominator by 3.

• Divide the numerator and denominator by 2.

• Divide the numerator and denominator by 3.

What is the equivalent fraction of 1/3 with a denominator of 6?

• 1/6

• 4/6

• 3/6

• 2/6

What is the sum of 3/6 and 2/6?

• 1/6

• 5/6

• 4/6

• 6/6

When adding fractions with the same denominator, what do you do with the denominators?

• Keep them the same.

• Add them together.

• Multiply them.

• Subtract them.

What is the first step in subtracting fractions with unlike denominators?

• Find the greatest common divisor.

• Find the lowest common multiple.

• Simplify the fractions.

• Convert them to improper fractions.

What is the lowest common multiple (LCM) of 4 and 8?

• 4

• 8

• 12

• 16

What is the result of subtracting 5/8 from 6/8?

• 4/8

• 3/8

• 2/8

• 1/8