5th Grade Adding and Subtracting Fractions
1 Adding and Subtracting Fraction Review
Whole Group: Roughly 15-20 minutes
- EXPLAIN to the students that you will be relearning how to add and subtract fractions with like denominators in word problems.
Adding Fractions with Like Denominators Question
- PLAY the Khan Academy “Piano” lesson. Stop the lesson after each arrow is drawn on the screen and DISCUSS why these arrows are important and why visuals are important. PLAY lesson. STOP after the equation ¾ - ¼ = is given. EXPLAIN why he chose to you subtraction in the equation. After the video ends, RE-EXPLAIN simplifying to the students and ASK if anyone has any questions.
- WRITE or PROJECT on the board a similar question: Sally is supposed to cut a loaf of bread into 8/12. She has already cut the bread into 4/12. What fraction does she still need to cut? WORK together as a class (asking them to give the step by step) to answer the question.
Subtracting Fractions with Unlike Denominators Question
- PLAY the Khan Academy “Lizard” lesson. STOP the lesson after he counts the extra 8 marks in the inch. DISCUSS and EXPLAIN why he has done this. PLAY lesson. STOP after he quickly say 8 goes into 17, 2 times with a remainder of 1. REMIND your students how this works. (18/4 = long division 18 divided by 4 = 4 goes into 18, 4 times with a remainder of 2. Do this with two more problems. 13/3 and 29/6). PLAY lesson. STOP after he counts off the additional 10. DISCUSS and EXPLAIN why he added the 10 instead of starting over. PLAY lesson. STOP before he gives the mixed number answer. STUDENTS WORK have the students try to get the correct answer. Have the students flip their paper over and put their pencils down once they work out the problem. PLAY lesson and show the answer. ASK the students to give a thumbs up or down if they got the answer correct. WALK around to see who missed it and pull them aside after the lesson.
- WRITE or PROJECT on the board a similar question:
Frank has a pencil with an eraser that is 5/6 long, and the wood section is 14/6 long. What is the length of the eraser and wood section of the pencil?
WORK together as a class (asking them to give the step by step) to answer the question.
Small Group Work Centers: 45 min with 15 min centers
- Group students into 3 groups of 6. Explain to the students that when they hear the timer they need to rotate clockwise within the classroom.
Center 1: Quizlet Flashcards - the students will access the Quizlet Fraction Flashcards and go through them until they hear the timer.
Center 2: Small Group with Teacher - In this group the teacher will have the Standards Mastery Adding and Subtracting Test A form projected for the group. The teacher will go through the 6 problems step by step assisting when needed.
Center 3: Woot Woot Math - The students will login to their Woot Woot account and work on the fraction refresher.
Key Standards Supported
Number And Operations—Fractions
Add and subtract fractions with unlike denominators (including mixed numbers) by replacing given fractions with equivalent fractions in such a way as to produce an equivalent sum or difference of fractions with like denominators. For example, 2/3 + 5/4 = 8/12 + 15/12 = 23/12. (In general, a/b + c/d = (ad + bc)/bd.)
Solve word problems involving addition and subtraction of fractions referring to the same whole, including cases of unlike denominators, e.g., by using visual fraction models or equations to represent the problem. Use benchmark fractions and number sense of fractions