Lesson 7 Multiply Three- and Four-digit Numbers by One-digit Numbers

    • Let’s multiply three- and four-digit numbers by one-digit numbers.

Warm-up Estimation Exploration: Mysterious Area

What is the area of the rectangle?

Rectangle. Horizontal side, 3 hundred ninety 5. Vertical side, 6.

Record an estimate that is:

too low

about right

too high

Activity 1 Larger Numbers to Multiply

Problem 1

Clare drew this diagram.

Diagram, rectangle partitioned vertically into 3 rectangles.

  1. What multiplication expression can be represented by the diagram?

  2. Find the value of the expression. Show your reasoning.

Problem 2

Consider the expression .

  1. Draw a diagram to represent the expression.

  2. Find the value of the expression. Show your reasoning.

Problem 3

Lin drew a diagram to represent .

  1. Complete Lin’s diagram.

    Diagram, rectangle partitioned vertically into 4 rectangles.

  2. Write an expression to represent the value of each part of the diagram.

  3. Find the value of . Show your reasoning.

Activity 2 Jada’s Errors

Problem 1

Jada used a diagram to multiply and made a few errors.

Diagram, rectangle partitioned vertically into 4 rectangles.

  1. Explain the errors Jada made.

  2. Find the value of . Show your reasoning.

Problem 2

  1. Find the value of . Show your reasoning.

  2. Find the value of . Show your reasoning.

Practice Problem

Problem 1

  1. Use the diagram to find the value of .

    Diagram, rectangle partitioned vertically into 3 rectangles.

  2. Find the value of .