Lesson 6

Solving Repeated Addition and Subtraction Problems

Est. Class Sessions: 2

Developing the Lesson

Part 3: Solving Repeated Addition and Subtraction Problems

Read the opening vignette on The Old Woman and Her Cats page as students follow along in the Student Activity Book. Have student pairs work on the problems on the pages. Allow students to use drawings, number lines, 100 Chart, and connecting cubes.

As students work, ask questions similar to the questions in Part 1 and in the Sample Dialog to help students understand the problem.

Use the Sample Dialog to guide your discussion of Questions 2A–2B of The Old Woman and Her Cats Page.

Teacher: How did you decide to start solving
Question 2A?

Jackie: I think it's 12 eyes.

Teacher: How did you decide to start solving
Question 2A?

Maria: I knew that there were 16 cats and she could feed
3 cats at each bowl.

Teacher: What did you need to find out?

Maria: I needed to find out how many bowls she would need.

Teacher: How did you solve it?

Maria: First, I drew 16 circles.

Teacher: What do the circles represent?

Maria: The circles are the cats.

Teacher: What did you do next?

Maria: I drew a box around every 3 circles.

Teacher: Why did you draw a box around every
3 circles?

Maria: Because I knew that she could feed 3 cats at every bowl. The boxes stand for the bowls.

Teacher: Great! What was your answer?

Maria: I drew 6 boxes but the last box only had
1 cat.

Teacher: What do the boxes around the circles represent?

Maria: There were 5 bowls with 3 cats but the last cat wouldn't fit anywhere, so I had to put it in a box by itself.

Teacher: Now let's go to Question 2B. Would she have room at the bowls for any more cats?

Jerome: Well, Maria just said that the last bowl had only
1 cat, so there's room for 2 more cats at that bowl.

Teacher: Nice thinking, Jerome!

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