B2.5 Add and subtract fractions, using appropriate strategies, in various contexts.
Activity 1: Eating in Groups (Addition and Subtraction of Fractions)
Materials
- manipulatives that can help with understanding fraction operations (fraction strips, fraction circles, rods, counters)
- grid paper
Divide the class into teams of 4 students.
Prepare cards with food-related situations.
Each team goes to a station to solve the problem written on the card.
Manage work time and rotate when time is appropriate.
Consolidation of Learning
Ask 2 teams per station to send you a photo of their work.
The members of the two selected teams present their approach to solving the problem.
Emphasize process and understanding.
Question the students during the presentation.
Examples of problems on the cards
- Ginette and Marc share a chocolate bar. Ginette ate \(\frac{1}{3}\) and Marc ate half of it. What fraction of the tablet is left?
- Zachary is baking 4 kinds of cookies for a bake sale to raise money for hisGrade 8 trip. Every recipe calls for flour.
- A group of students prepare to order 9-inch pizzas for a party.
Chocolate chip cookies: \(1\frac{1}{2}\) cups
Oatmeal cookies: \(\frac{3}{4}\) cup
Sugar Cookies: \(\frac{2}{3}\) cup
Molasses Cookies: \(2\frac{1}{4}\) cups
How much flour does he need in order to make the 4 types of cookies?
Mohammed wants \(\frac{1}{2}\) of a pizza.
Katrina wants \(\frac{1}{3}\) of a pizza
Gigi wants \(\frac{5}{6}\) of a pizza
Axel wants \(\frac{3}{4}\) of a pizza
Vlad wants \(\frac{3}{8}\) of a pizza
How many pizzas are needed? Will there be any left? If so, what fraction?
Activity 2: Fraction Puzzle (Addition and Subtraction)
Divide the class into teams of 4 students.
Each team builds an expression puzzle containing addition and subtraction on fractions.
Distribute a template (blank grid of \(4\; \times \;4\)) as below.
The student must ensure that for each common segment, they write an expression with its answer.
For example, \(\frac{3}{4}\; - \;\frac{1}{2}\; + \;\frac{1}{4}\)(expression) and \(\frac{ 1}{2}\) (answer to the expression) must be on either side of the common segment (see grid).
When completed, each team's puzzle should look like this.
Cut out each square.
All teams should have a 16-piece puzzle.
Swap puzzles between teams.
The goal of the game is to remake the puzzle with the right pieces in the right places (expression = right answer).
Students should have paper and pencil to work with.