Lesson 2

More Multiplication Stories

Est. Class Sessions: 2

Developing the Lesson

Part 2. Break-Apart Products and Matching Stories

Many of the ways students solve their multiplication problems will involve breaking numbers apart into sums of easier products as in the example methods. Ask students to read the first page of the More Multiplication Stories pages in the Student Guide.

Point out that Peter wrote two stories. Notice the first story does match the multiplication problem but it does not match the way he solved the problem. Since he broke 26 into two parts (25 + 1), he made 25 chickens brown and 1 chicken red in each of the 4 pens. His story now matches the way he solved the problem.

Ask:

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  • How does Peter's first story match 4 × 26? (4 times 26 means 4 groups of 26 things. In Peter's story, there were 4 pens. Those were the groups. Each pen held 26 chickens.)
  • How did Peter solve the problem? (He broke the 26 into two parts, 25 + 1. Then he multiplied each part by 4.)
  • How did he multiply 4 × 25? (He doubled it two times. Doubling one time is like multiplying by two. Doubling again is like multiplying by four.)
  • How is his second story different from his first story? (He gave more details about the chickens. He said there were 25 brown chickens and 1 red chicken.)
  • Why do you think he gave those extra details? (It is like breaking 26 into two parts. It matches the way he solved the problem.)
  • What does 4 × 25 describe? (the number of brown chickens in all the pens)
  • What does 4 × 1 describe? (the number of red chickens in all the pens)

Select volunteers to describe their solutions to 4 × 26 from Part 1 that involved breaking numbers apart. Ask them to share the corresponding stories they wrote.

For each story and solution shared, ask:

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  • Does this story match the way the numbers were broken apart? If yes, how? If not, how can we rewrite the story so that it matches? (See Sample Dialog for an example.)
  • Did anyone break 26 into tens and ones? Explain how you did that to solve 4 × 26. (26 is the same as 20 + 6. 4 × 20 + 4 × 6 is 80 + 24, or 104.)
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Teacher: Did anyone solve 4 × 26 by breaking numbers apart?

Tina: I did. I said: 26 = 10 + 10 + 6. Then I multiplied 4 × 10 (twice) and 4 × 6. I added up my answers.

Teacher: What was your story?

Tina: I said, “There were 4 boxes of popsicles. Each box had 26 popsicles. How many popsicles were there in all?”

Teacher: That matches 4 × 26. Can you add more details to your story so it matches the way you solved the problem?

Tina: I could tell the flavor of the popsicles. There were 10 cherry popsicles, 10 grape popsicles, and 6 orange popsicles.

Teacher: That is a good idea. Then what does 4 × 10 count?

Tina: It counts the cherry popsicles in all the boxes. It also counts the grape popsicles.

Teacher: What is 4 × 6?

Tina: It is the number of orange popsicles. I added the number of each flavor and I got the total of all the popsicles in all the boxes.

Student Guide: 366
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SG_Mini
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Student Activity Book:
Master: