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Chapter 14

Part 1: Home and School Investigation

Send the Letter to Family (PDF file) home with each child. Once each one of them has brought in a picture with a number sentence, put the children in pairs. Have each child share his or her picture and subtraction sentence with the other child. A good time to do this activity is after Lesson 6 on practicing subtraction.

Part 2: Be an Investigator

A good time to do this investigation is after Lesson 6 on practicing subtraction.

Introducing the Investigation

Ask, What kind of shoes do you have on? Do your shoes tie, buckle, close with velcro, or slip-on? Show children the labels made from the Investigator Worksheet. Tell them you are going to put the labels on the floor and you want them to put only one of their shoes in one of the piles according to what kind of shoe it is.

Doing the Investigation

As children are putting their shoes in the appropriate pile, remind them to add only one shoe. They should have one shoe left on.

When each child has put a shoe in one of the piles, tell the children that they are going to organize the shoes in straight lines so it is easier to see how many of each kind there are. Then have the children organize the shoes in straight vertical lines with a label below each group. They will actually be creating a concrete graph showing the kinds of shoes they wear. Make sure that each shoe takes the same amount of space so that, for example, a line of four shoes of one kind takes the same amount of space as a line of four shoes of a different kind. This is very important because the students will be comparing the lines of shoes to see the differences in the amounts of each type of shoe.

When the shoe graph is finished, ask questions such as:

• How many slip-on shoes do we have?
• How many more tie shoes do we have than buckle shoes?

Ask as many questions about the differences as you can. Children should be able to look at the graph and count how many more shoes are in one column than another. Each time, have the children tell you what number sentence to write on the board to show the difference. For example, if there are 5 tie shoes and 9 buckle shoes, write 9 − 5 = 4.