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!
Grades:
View aligned standards
Learning Objectives
Students will be able to add and subtract mixed numbers by converting them into improper fractions and back again.
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.