Lesson 18 Diagrams and Equations for Word Problems

    • Let’s connect diagrams and equations to situations.

Warm-up Notice and Wonder: Diagrams

What do you notice? What do you wonder?

Diagram. One rectangle split into 2 parts. Total length, question mark. One part labeled 142, the other part labeled 20.
Diagram. One rectangle split into 4 parts. Each part labeled 5. Total length, question mark.
Diagram. One rectangle split into 5 parts. Total length, question mark. One part labeled 142, the other four parts all labeled 5.

Activity 1 Card Sort: Situations, Equations, and Diagrams

Your teacher will give you a set of cards showing situations, equations, and diagrams.

Sort the cards into groups so that the cards in each group represent the same situation. Be ready to explain your reasoning.


Clare had 225 beads. A friend gave her a pack of 48 beads. Then she used 70 beads to make a necklace. How many beads does Clare have now?


Diagram. One rectangle split into 8 parts. One part labeled 225. Other 7 parts labeled 10. Total length, question mark.



Elena has 7 notebooks. Each notebook has 10 paper clips in it. Elena also has a box of 225 paper clips. How many paper clips does Elena have?




Andre has 225 crayons. He buys 6 more packs and each pack has 10 crayons. How many crayons does Andre have now?


225 number tape made up of ?+10+10+10+10=10+10


Diego has a collection of 225 baseball cards. He gets 35 more cards from a friend, then buys 72 cards. How many cards does Diego have now?


Han has 225 beads. Then he makes 6 bracelets for his friends. Each bracelet has 10 beads. How many beads does Han have now?


number tape 225+35+72=?


Activity 2 Makes Sense to Me: A Gallery Walk

  1. Your teacher will assign a problem to your group. Work together to solve your assigned problem.

  2. Create a poster of your group’s solution. Organize your work so that it can be followed by others.

  3. As you visit other groups’ posters, consider how each answer makes sense.

    Choose one poster and make a comment on the solution. Write on your sticky note how you know the answer makes sense.

Practice Problem

Problem 1

Select all equations that match the tape diagram.

Diagram. One rectangle split into 6 parts. Total length, 110. 1 part, labeled question mark. Other 5 parts labeled 6.