Lesson objective: Solve multi-step problems involving sums and differences of fractions with different sized pieces.

This lesson provides an opportunity for students to apply their knowledge and understanding of addition and subtraction of fractions with different sized pieces to a real-life situation. Students are asked to compute the amount of paper needed for decorating a classroom, then identify two values from a list that may be used to find the missing value.

Key Concept students will use:

Skills students will use:

- Find equivalent fractions (Grade 3, Unit 10)
- Calculate sums and differences of fractions in multi-step expressions

Students engage in Mathematical Practice 4 (Model with mathematics) as they apply the mathematics they know to solve problems arising in everyday life. Students use tools, such as tape diagrams, to analyze relationships between quantities and draw mathematical conclusions.

**Key vocabulary: **

- sum
- difference
- equivalent
- decompose
- denominator

**Special materials needed:**

- Students may need fraction tape for intervention.