Lesson 15 Diagrams with All Kinds of Compare Problems

    • Let’s connect Compare problems to diagrams.

Warm-up Number Talk: 10 and Some More

Find the value of each sum mentally.

Activity 1 Shell Collections

Student on the beach

Diego has 55 shells. Lin has 20 fewer shells than Diego.

  1. Use the story problem to complete the diagram.

    Diagram. Two rectangles of equal length. Rectangle on top not labeled, partitioned into 2 parts. First part, shaded, total length, question mark. Second part has dashed outline, total length, 20. Rectangle on the bottom not labeled, shaded, total length, 55.

  2. Write an equation to show how you could find the unknown number of shells. Use a question mark to represent the unknown.

Activity 2 Card Sort: At the Beach

  1. Read a card with a story problem.

  2. Find cards that match the story problem.

  3. Explain why the cards match.

Practice Problem

Problem 1

There are 25 crickets chirping in the front yard.

There are 16 fewer crickets chirping in the front yard than in the back yard.

  1. Label the rectangles to match the story. Explain your reasoning.

    Diagram. Two rectangles of equal length. Rectangle on top blank label, partitioned into 2 parts. First part, shaded, total length, 25. Second part has dashed outline, total length, 16. Rectangle on the bottom blank labeled. Total length, question mark.

  2. Write an equation to represent the story problem.