Lesson 5

Subtract Mixed Numbers

Est. Class Sessions: 2–3
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Mathematical Standards

5.NF.A
Use equivalent fractions as a strategy to add and subtract fractions. (5.NF.A.1, 5.NF.A.2)
5.NF.B
Apply and extend previous understandings of multiplication and division. (5.NF.B.4, 5.NF.B.6, 5.NF.B.7)

Standards for Mathematical Practice

MP1.
Make sense of problems and persevere in solving them.
MP2.
Reason quantitatively.
MP3.
Construct viable arguments and critique the reasoning of others.
MP4.
Model with mathematics.
MP5.
Use appropriate tools strategically.
MP6.
Attend to precision.
MP7.
Look for and make use of structure.
MP8.
Look for and express regularity in repeated reasoning.

Students use fraction circle pieces to model the subtraction of mixed numbers and to develop paper-and-pencil procedures. They use add mixed numbers to check their subtraction. Students play Closest To, a game involving estimation and subtraction.

Content in this Lesson

  • Representing subtraction of mixed number fractions with fraction circle pieces, number lines, and number sentences [E3].
  • Adding and subtracting mixed number fractions including those with unlike denominators using fraction circle pieces and paper-and-pencil methods [E8].
  • Solving word problems involving subtraction of mixed number fractions [E5].
  • Finding equivalent fractions using tools (e.g., area models, number lines) and multiplication and division strategies [E1].
  • Finding common denominators and using them to subtract and compare fractions [E10].
  • Estimating differences of mixed number fractions using benchmarks and mental math strategies [E9].
  • Representing and identifying the simplest form of a fraction using tools (e.g., area models) and multiplication and division strategies [E2].
  • Choosing appropriately from among estimation and computation strategies [E7].
  • Finding strategies for adding and subtracting mixed numbers [MPE2].
  • Using estimation and addition to check subtraction problems [MPE3].
  • Knowing the question to answer and what is important in a word problem [MPE1].
  • Using labels to show what numbers mean [MPE6].
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Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Books

 Student Guide
Student Activity Book      

Teacher Resources

 Teacher Guide - digital

Supplies for Students

  • fraction circle pieces
  • scissors
  • 12-inch ruler, optional

Materials for the Teacher

Materials Preparation

Prepare Closest To Game Cards. Copy the Closest To Game Cards Master on heavy paper or card stock.

Assessment in this Lesson

Assessment Expectation Assessed Math Practices Expectation Assessed

Subtract Mixed Numbers
Check-In: Questions 8–11
Student Guide
Page 476
and the corresponding
Feedback Box
Teacher Guide - digital
E1.
Identify and find equivalent fractions using tools (e.g., area models, number lines) and multiplication and division strategies.
E2.
Represent and identify the simplest form of a fraction using tools (e.g., area models) and multiplication and division strategies.
E8.
Add and subtract fractions including those with unlike denominators using area models and paper-and-pencil methods.
E9.
Estimate sums and differences of fractions using benchmarks and mental math strategies.
E10.
Find common denominators and use them to add, subtract, and compare fractions.
MPE2.
Find a strategy. I choose good tools and an efficient strategy for solving the problem.
MPE3.
Check for reasonableness. I look back at my solution to see if my answer makes sense. If it does not, I try again.

DPP Item O
Estimate and Solve
Teacher Guide - digital
E9.
Estimate sums and differences of fractions using benchmarks and mental math strategies.