In the associated Algebra 1 lesson, students expand expressions such as \((x+3)(x+8)\) by relating the expressions \(x+3\) and \(x+8\) to side lengths of a rectangle and using the distributive property. In this supporting lesson, students work with numerical expressions and reason about equal numerical expressions before representing side lengths with variables. Students make use of the structure of expressions and rectangles to reason about equivalent expressions (MP7).
Lesson overview
- 8.1 Warm-up: Ways to Express the Area (10 minutes)
- 8.2 Activity: Multiplying Two-Digit Numbers and the Distributive Property (15 minutes)
- 8.3 Activity: Using the Distributive Property to Write Equivalent Expressions (20 minutes)
Learning goals:
- Identify and use the structure of expressions to multiply two numbers which can be written as sums.
- Understand, by writing different expressions to represent area diagrams, that expressions can look different but be equivalent.
Learning goals (student facing):
- Let’s write different expressions to represent the same area.
Standards:
- This lesson builds on the standards: CCSS.4.NBT.B.5MS.4.NBT.5CCSS.6.EE.A.3MS.6.EE.3MO.4.NBT.A.6MO.6.EEI.A.3
- This lesson builds towards the standard: CCSS.HSA-SSE.B.3MS.A-SSE.3MO.A1.SSE.A.3aMO.A1.SSE.A.3b
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