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## Chapter 19

### Part 1: Home and School Investigation

Send the Letter to Family (PDF file) home with each child. Once all the children have brought in a picture of fingers showing a number, work with the children to sort the pictures. Put together all the pictures that show the number 11, that show the number 12, etc. You might want to display the pictures in groups in the classroom. A good time to do this activity is after Lesson 2 on adding with 10.

### Part 2: Be an Investigator

A good time to do this investigation is after Lesson 5 on names for numbers.

#### Materials

• counters
• small pieces of paper(in a bag), each labeled with the number 13, 14, 15, or 16

#### Introducing the Investigation

Write the number 16 on the board. Ask the children for two numbers less than 10 that when added together give 16 as an answer. Write what they say on the board and ask if there is another way.

Tell the children that you are going to put them in pairs. Each pair will choose a number. Their job is to find as many ways as they can to add numbers less than 10 to get that number. Tell them that they can use counters to help them. Tell them to record their results on a piece of paper.

#### Doing the Investigation

If children are having trouble with this, help them use the counters. Show them how to count out the target number of counters and then separate that group of counters into two groups.

• 13
• 6 + 7
• 7 + 6
• 8 + 5
• 5 + 8
• 9 + 4
• 4 + 9
• 14
• 7 + 7
• 8 + 6
• 6 + 8
• 9 + 5
• 5 + 9
• 15
• 7 + 8
• 8 + 7
• 9 + 6
• 6 + 9
• 16
• 8 + 8
• 9 + 7
• 7 + 9

#### Extending the Investigation

Have children do the same activity with a different number.