 |
|
 |
|
 |
 |
|
|
|
|
Key
Idea
Place value can
help you round
numbers. |
|
|
Vocabulary
• rounding
|
|
|
Materials
• grid paper |
|
 |
Rounding Whole
Numbers and Decimals |
 |
|
 |
|
 |
|
 |
What is the number closest to? |
 |
|
| a. |
Draw a number line like the one shown. Then locate each
number and tell if it is closer to 5 million or 6 million. |
|
 |
|
|
5,765,302
5,534,227 |
5,483,198
5,297,430 |
 |
|
| b. | Draw
another number line like the one below. |
|
Show each number and tell if it is
closer to 3.4 or 3.5. |
| 3.47 |
3.43 |
3.457 |
|
 |
|
 |
|
 |
|
|
 |
|
| How can you round whole numbers and decimals? |
|
|
Rounding
is a process that tells which multiple of
10, 100, 1,000, etc., a number is closest to. |
|
 |
 |
 |
|
|
 |
|
 |
Round 63,283,025 to
the nearest million. |
 |
Round 35.846 to the
nearest hundredth. |
 |
|
 |
|
 |
Find the rounding place. |
 |
63,283,025 |
 |
35.846 |
|
 |
|
 |
Look at the digit to the
right of the rounding place. |
 |
 |
 |
 |
|
 |
 |
 |
|
| If
it is 5 or more, change the number to the next
larger multiple of 10, 100, 1,000, etc. If it
is less than 5, change to the next smaller multiple. |
 |
Since 2 < 5,
63,283,025 rounds
to 63,000,000. |
 |
Since 6 > 5,
35.846 rounds
to 35.85. |
|
 |
|
 |
Talk About It |
|
|
|
1. In Example B, explain why we write 35.85 and not 35.850. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|