Lesson 10

The purpose of this lesson is for students to use area diagrams to explore multiplication strategies based on properties of operations. 

Previously, students examined patterns in the multiplication table and used them to find products within 100 and to notice properties of multiplication—the commutative property, in particular. In this lesson, they analyze strategies for finding the area of rectangles to explore distributive and associative properties. They study gridded rectangles that have been decomposed into smaller parts and expressions that represent how the decomposition could help us find the area. Students see how the strategies, along with the diagrams and the expressions that represent them—can help us find the product of two numbers. 

As students make sense of expressions and interpret them in terms of parts of area diagrams (MP1), they practice reasoning quantitatively and abstractly (MP2).

Reflect on times you observed students listening to one another’s ideas today in class. What norms would help each student better attend to their classmates’ ideas in future lessons?