# Lesson 3: The Thousands Places

## Getting Started

### Questions to Explore

- How does place value work?
- How can we use place value to name, create, and compare numbers to a million?
- How do we write and speak in mathematical language?

### Facts and Definitions

**Base-10 number system**: a commonly used number system that is based on 10 digits (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) and the number 10**Ten thousands place**: position to the left of the thousands place**Hundred thousands place**: position to the left of the ten thousands place- Numbers of four digits or more require commas. To place commas, start to the right of the ones place and count three places to the left. Repeat as needed starting at the comma and counting three more places to the left.

### Skills

- Read and write multi-digit whole numbers using base-ten numerals, number names, and expanded form
- Recognize that in a multi-digit whole number, a digit in one place represents ten times what it represents in the place to its right

### Materials

- calculator
- fine point dry-erase markers (kit)
- Interactive Notebook
- laminated place value chart (kit)
- number cards (kit)
- whiteboard (kit)

### Introduction

Materials: calculator, fine point dry-erase markers (kit), whiteboard (kit)

Write 1, 10, 100, and 1,000 in a column on the whiteboard as shown. Leave space below 1,000 to add additional numbers. (If your child already knows where to insert commas in numbers, include the commas; otherwise, leave them out.)

Tell your child to say the numbers aloud as he points to them, and ask, "What do you see happening to these numbers?" He may note that they're getting bigger and that a zero is being added to each number to create the next one. Ask, "What do you think the next number is?" (10,000) Tell him to write the next two numbers on the whiteboard. He should write 10,000 and 100,000. Don't worry about the commas that belong in the numbers at this point if your child doesn't yet know where to add them.

Now, ask, "What number is each of the numbers being multiplied by to get to the next one? For example, what do we multiply by 1 to get to 10?" Help your child see that starting at 1, each number is being multiplied by 10 to get to the next number. Ask, "What happens when you multiply any number by 10?" Your child should note that you add a zero to the end of the number. To review this, write 5x10 and 10x9 on the whiteboard, and tell your child to find the products (50 and 90). Ask him to prove that this is true by entering a one-digit number on a calculator and then multiplying by 10 several times so that he can see the number growing with additional zeros.

Explain that our number system is based on the number 10 and that understanding this system makes working with big numbers much easier.

Next, provide time for your child to watch the video at the following web link. This video discusses the base-10 number system and rules and patterns in place value. It also introduces numbers beyond one million and reviews expanded form. Much of this video should be review for your child, but it will give him a solid foundation for working with large numbers.

Explain that our number system is based on the number 10 and that understanding this system makes working with big numbers much easier.

Next, provide time for your child to watch the video at the following web link. This video discusses the base-10 number system and rules and patterns in place value. It also introduces numbers beyond one million and reviews expanded form. Much of this video should be review for your child, but it will give him a solid foundation for working with large numbers.

Say, "This video talked about some really big numbers going all the way up to one billion. Before you can work with those kinds of numbers, it's important that you understand patterns in our number system. You've already talked about how we can multiply by 10 to make numbers greater, but now you're going to look at our number system in a slightly different way."