How do you find the difference between three-digit numbers

without drawing out any pictures?

578 - 321= ?

In this lesson you will learn how to add three-digit numbers by

using expanded form.

Let’s Review

Expanded form of a number:

2 2 2

200 + 20 + 2

A Common Misunderstanding

Some people add the numbers they see, not their values.

2 2 2

2 + 2 + 2

Core Lesson

What is 869 - 341 ?

800

60

9

500 20 8

+

+ 528

- 40 - 1

- 300

Core Lesson

500 70 8

- 300

What is 578 - 321?

200 50 7

++ 257

578 - 321= ?

- 20 - 1

Core Lesson

What is 758 - 606 ?

700 50 8

100 50 2

++ 152

- 0 - 6

- 600

In this lesson you have learned to add three-digit numbers by

using expanded form.