## Chapter 15

### Part 1: Home and School Investigation

Send the Letter to Family (PDF file) home with each child. Once all the children have brought in the addition sentences that show the total number of people in their families, put the children in pairs. Have them compare their families in terms of the number of children, the number of teenagers, the number of adults, and the total number of people in the family.

A good time to do this activity is after Lesson 6 on adding three numbers.

### Part 2: Be an Investigator

A good time to do this investigation is after Lesson 6 on adding three numbers.

#### Materials

- Investigator Worksheet (PDF file) for each group of three children
- bag with four pieces of paper numbered from 1 to 4 (for each group of three children)

#### Introducing the Investigation

Show the children the bag with the numbered pieces of paper. Tell them that they are going to work in groups of three. Each child in the group will draw a number, and the group will work together to find the sum of the three numbers. Have three volunteers help you demonstrate the activity. Have one child draw a number. Record that number in the first row of the table on the worksheet. Then put the piece of paper with the number on it back in the bag. Have the second child and the third child do the same thing. When they have finished, find the sum of the three numbers and record the sum in the table.

Put the children in groups of three to do the investigation.

#### Doing the Investigation

Remind the children to put the numbered piece of paper back in the bag after recording the number on the worksheet.

When the children have completed the chart by doing the activity five times, have them answer the questions at the bottom of the sheet. Discuss the answers with the children. Ask them to talk about how they figured out the least sum possible and how they figured out the greatest sum possible using any of the numbers on the chart.

Possible Answers:

Here is how we would get the least sum.

__ 1 __ + __ 1 __ + __ 1 __ = __ 3 __

Here is how we would get the greatest sum.

__ 4 __ + __ 4 __ + __ 4 __ = __ 12 __

#### Extending the Investigation

Have the children repeat the activity to get sums through 18, using a number cube with the numbers 1 through 6 on it.