Addition of Fractions with Unlike Denominators

Examples, solutions, and videos to help Grade 4 students learn how use visual models to add two fractions with related units using the denominators 2, 3, 4, 5, 6, 8, 10, and 12.

Common Core Standards: 4.NF.3a, 4.NF.3d, 4.NF.1, 4.MD.2

NYS Common Core Grade 4 Module 5, Lesson 20

Grade 4, Module 5, Lesson 20 Worksheets

Lesson 20 Concept Development
Problem 1: Add unit fractions with related denominators using tape diagrams.
1/3 + 1/6 =

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Lesson 20 Problem Set

1. Use a tape diagram to represent each addend. Decompose one of the tape diagrams to make like units. Then write the complete number sentence. Part (a) is partially completed.
   a. 1/4 + 1/8
   b. 1/4 + 1/12
   c. 2/6 + 1/3
   d. 1/2 + 3/8
   e. 3/10 + 3/5
   f. 2/3 + 2/9
2. Estimate to determine if the sum is between 0 and 1 or 1 and 2. Draw a number line to model the addition. Then write a complete number sentence. Part (a) has been completed for you.
   a. 1/2 + 1/4
   b. 1/2 + 4/10
   c. 6/10 + 1/2
   d. 2/3 + 3/6
   e. 3/4 + 6/8
   f. 4/10 + 6/5
3. Solve the following addition problem without drawing a model. Show your work.
   2/3 + 4/6

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Lesson 20 Homework

1. Use a tape diagram to represent each addend. Decompose one of the tape diagrams to make like units. Then write the complete number sentence. Part (a) is partially completed.
   a. 1/3 + 1/6
   b. 1/2 + 1/4
   c. 3/4 + 1/8
   d. 3/4 + 1/8
   e. 1/4 + 5/12
   f. 3/5 + 3/10
2. Estimate to determine if the sum is between 0 and 1 or 1 and 2. Draw a number line to model the addition. Then write a complete number sentence. Part (a) has been completed for you.
   a. 1/3 + 1/6
   b. 3/5 + 7/10
   c. 5/12 + 1/4
   d. 3/4 + 5/8
   e. 7/8 + 3/4
   f. 1/6 + 5/3
3. Solve the following addition problem without drawing a model. Show your work.
   5/6 + 1/3

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