Lesson Plan

Single Strategy for Adding and Subtracting Mixed Numbers

Teach your students to add and subtract fractions with like denominators using a strategy that works for both operations: converting mixed numbers into improper fractions and back again!
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Need extra help for EL students? Try the Explain Fraction Conversions pre-lesson.
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Need extra help for EL students? Try the Explain Fraction Conversions pre-lesson.

Learning Objectives

Students will be able to add and subtract mixed numbers by converting them into improper fractions and back again.

The adjustment to the whole group lesson is a modification to differentiate for children who are English learners.
EL adjustments

Introduction

(5 minutes)
  • Show your class two examples:
    • a whole piece of fruit and ¼ slice to represent 1 ¼,
    • another model of 1 and ¼ of fruit, where the whole has been partitioned into ¼ pieces.
  • Ask your class which would be easier to subtract ¾ from and why. Have your students turn to a neighbor and share their thoughts.
  • Allow students to share out to the whole class and tease out the notion that it's easier to subtract from whole items already in a group of like pieces.
  • Share that today's lesson uses a strategy for adding and subtracting mixed numbers by first making them improper fractions, or as a group of like or same-sized pieces.
  • Point out to your students that mixed numbers are different from improper fractions in that they include a whole number and a proper fraction (where the numerator is less than the denominator).

Beginning

  • Allow students to use their home language (L1) or new language (L2) in their discussions.
  • Provide papers for them to model the teacher's actions during the questioning and then label the pieces of paper to help them remember the key terms ("improper fractions," "groups," "same-sized portions," etc.).
  • Have them turn and talk about the meaning of same-sized shapes and the importance when dealing with fractions.

Intermediate

  • Write the academic language students can use throughout the lesson on the board as you introduce the language.
  • Provide the following sentence frames to assist in their discussion:
    • "I think________."
    • "This is the best way because________."
  • Ask them to rephrase the meanings for improper fraction and mixed number to show their understanding. Allow them to use visuals in their explanations.