# Lesson 11

Estrategias de multiplicación para rectángulos sin cuadrícula

### Lesson Purpose

The purpose of this lesson is for students to represent multiplication strategies on an ungridded rectangle.

### Lesson Narrative

Previously, students used gridded rectangles to represent strategies based on the distributive and associative properties. Here, they use the same strategies, but represent them on an area diagram without a grid. Then, students match expressions that could represent the area of the same rectangle, without using diagrams. The reasoning helps students work toward fluent multiplication within 100.

• Engagement
• MLR2

### Learning Goals

Teacher Facing

• Apply associative and distributive properties of multiplication to find products within 100.
• Recognize that multiplication is associative and can be distributed over addition.

### Student Facing

• Usemos diferentes estrategias para encontrar el área de rectángulos sin cuadrícula.

### Required Materials

Materials to Copy

• Centimeter Grid Paper - Standard
• Card Sort: Different Expressions, Same Rectangle

### Required Preparation

Activity 2:

• Create a set of cards from the blackline master for each group of 2 or 4.

### Lesson Timeline

 Warm-up 10 min Activity 1 15 min Activity 2 20 min Lesson Synthesis 10 min Cool-down 5 min

### Teacher Reflection Questions

Which students came up with an unexpected strategy in today’s lesson? What are some ways you can be more open to the ideas of each and every student?

### Suggested Centers

• Rectangle Rumble (3–5), Stage 3: Factors 1–10 (Addressing)
• Capture Squares (1–3), Stage 7: Multiply with 6–9 (Addressing)