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!
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.