Lesson 4

Pocket Parts

Est. Class Sessions: 2

Developing the Lesson

Part 1: Combining Two Parts and Finding the Whole

Ask students to make a cube train using one color for the number of their shirt pockets and another cube train using a second color of the number of their pants pockets. Have students join the two trains. This represents the total number of pockets.

X

To provide additional examples for classes with a small number of students, tell students to imagine wearing clothing with a different number of pockets than the ones worn to class today. For example they might think of an outfit they might change into after school, a favorite outfit, or one they'd wear to a party. Tell individual students to imagine a change of clothing with a specified number of pockets on a shirt and pants that you randomly assign. Tell them to build two additional cube trains to represent the imaginary outfit.

X

Research from the Cognitively Guided Instruction (CGI) Project provides interesting observations about children's approaches to problem solving. The researchers observe that there is a great deal of commonality in the strategies that children use to solve word problems. A child typically moves through these three states: modeling, counting, and using derived number facts. Children move back and forth through the strategies depending on the size of the numbers. At the same time, there is a great deal of variability in the ages at which children use different strategies (Carpenter, et al., 1999).

Observe students as they work in pairs to complete the tasks in this lesson. Encourage them to explain or model how they solved the problems so that you can understand the different strategies individual students use.

X

The Mathematics in this Unit provides information on addition problem types. This document emphasizes the importance of children using strategies that make sense to them.

Ask students to turn to Question 1 on the Shirt and Pants Pockets pages in the Student Activity Book and record the number of shirt and pants pockets they counted on their clothes and with their cube trains. Ask each student to write a number sentence representing the number of pockets on his or her clothing. As an example, write a number sentence for the number of pockets on your clothing on a display of the pages.

Ask several students to explain to the class how many shirt pockets, pants pockets, and total pockets they have. Also ask them to share their number sentences.

Have students complete Questions 2–3 to practice finding the total number of pockets and writing number sentences on the Shirt and Pants Pockets pages in the Student Activity Book using various strategies. See Figure 2. Students may complete these individually or with a partner. Discuss Questions 2–3 with the class before asking students to complete the page. See Sample Dialog 1 to guide discussion of Questions 2–3.

X

Use this Sample Dialog to discuss student strategies for Questions 2 and 3 on the Shirt and Pants Pockets pages in the Student Activity Book.

Teacher: In Question 2, there is one shirt pocket and four pants pockets. What can you do to figure out the total number of pockets on the shirt and pants? What tools or strategies can you use? Tell me how you will use them.

Michael: I just counted: four, five. So, you know that one more than four is five.

Irma: You can see on the number line.

Teacher: What do you see?

Irma: That one more than four is five. If you go one hop past four, you land at five, so five pockets.

Teacher: Excellent thinking. In Question 3, there are two shirt pockets and three pants pockets. What tools or strategies can you use to find the total?

Jessie: I counted them.

Teacher: How did you count them?

Jessie: I started with three because it is bigger and I counted three, four, five. So there are five.

Jackie: I did the same thing, except I made a train with two red cubes and three yellow cubes first. Then I counted the cubes in the train.

Grace: I drew dots and counted them

Teacher: That's a good idea. Tell me more about what you did. Where did you put them?

Grace: I put two dots by the shirt and three dots by the pants. Then I counted to five.

Teacher: Those are all good strategies. When you solve the rest of the problems, try different tools and strategies for different problems.

Assign the Pocket Parts page in the Student Activity Book. Note that students write number sentences on lines on these pages.

X

Observe students as they solve problems on the Shirt and Pants Pockets pages in the Student Activity Book to assess their abilities to use the counting-on strategy [E5] and tools (connecting cubes and counters) to solve two-part addition problems [E7].

For targeted practice, make additional problems using the More Pocket Parts 1 and 2 Masters. Be sure students have connecting cubes, counters, and number lines available to support their strategies for solving different types of problems.

Adventure Book:
Student Activity Book:43 44 45
Answers
X
SAB_Mini
+
X
SAB_Mini
+
X
SAB_Mini
+
Master:
Two possible strategies for solving pocket problems
X
+