Help with Opening PDF Files

## Chapter 10

### Part 1: Home and School Investigation

Tell the class that you would like them to gather something that is easy to collect and count, for example plastic bottle caps. Tell students to continue to collect them until they have 100. Decide with the class what you will collect. Then write what you have decided to collect in the space provided and send the Letter to Family (PDF file) home with each child.

Collect the items from the children each day. When the children have collected 10 or more, group 10 together, put them in a plastic bag, and label the bag 10. Each day show the bags and the individual items. Ask, How many do we have now?

Continue doing the activity until you have 100 items.

### Part 2: Be an Investigator

A good time to do this investigation is after Lesson 6 on different ways to show numbers.

#### Introducing the Investigation

Ask children if they have ever been to a bakery. You might want to read a book about bakeries to the children. For example, Ruth's Bake Shop by Kate Spohn is about an octopus that opens a bakery. Ask the children to talk about the kinds of things they have seen sold in a bakery, such as cookies, cupcakes, bread, etc. Tell children that they are going to create a bakery bulletin board.

Put the children in pairs.

#### Doing the Investigation

Give each group a copy of the Investigator Worksheet (PDF file) and tell them that they are going to create a tray of goodies for the bakery. Tell them they need to first think of the item that will be on the tray. Then they need to decide how many of the item they will put on the tray. Tell the children they need to put between 20 and 100 items on the tray. Ask them to group their items by tens to make for easy counting. Have them write the number of items and what kind of item it is on the back of the Investigator Worksheet.

When children are finished, display the completed worksheets on the board. You can use the bulletin board to play guessing games with the children. For example:

I am thinking of an item. When the number of this item is written out, there is a 4 in the tens place and a 5 in the ones place. What am I thinking of?

Have the children point to the picture they think you are describing. Since the children grouped their bakery items by tens, it should make it easy to spot the item.