Instructions
Welcome, Rounding Master! To round a number, we find which "friendly" number (like a 10 or 100) it's closest to. Here's the secret rule:
- Look at the digit to the right of the place you are rounding to.
- If the digit is 4 or less, let the number rest (round down).
- If the digit is 5 or more, raise the score (round up)!
Part 1: Rounding to the Nearest 10
Look at the ones digit to decide if you round up or down. Your final answer must end in a zero!
- 1. 48 rounds to
- 2. 72 rounds to
- 3. 35 rounds to
- 4. 91 rounds to
- 5. 156 rounds to
Part 2: Rounding to the Nearest 100
This time, look at the tens digit. Your final answer must end in two zeros (00)!
- 1. 170 rounds to
- 2. 425 rounds to
- 3. 850 rounds to
- 4. 681 rounds to
- 5. 249 rounds to
Part 3: The Rounding Master Mix-Up!
Read the instructions carefully! Round each number two different ways.
| Number | Round to the Nearest 10 | Round to the Nearest 100 |
|---|---|---|
| 138 | ||
| 572 | ||
| 895 |
Part 4: Brain Teaser Challenge
Read the problem and use your rounding skills to find the answer.
Leo counted 243 stars with his telescope on Monday and 185 stars on Tuesday. About how many stars did he see in total? First, round each number to the nearest hundred, then add them together.
Monday (rounded):
Tuesday (rounded):
Total (about):
Answer Key
Part 1: Rounding to the Nearest 10
- 48 rounds to 50
- 72 rounds to 70
- 35 rounds to 40
- 91 rounds to 90
- 156 rounds to 160
Part 2: Rounding to the Nearest 100
- 170 rounds to 200
- 425 rounds to 400
- 850 rounds to 900
- 681 rounds to 700
- 249 rounds to 200
Part 3: The Rounding Master Mix-Up!
| Number | Round to the Nearest 10 | Round to the Nearest 100 |
|---|---|---|
| 138 | 140 | 100 |
| 572 | 570 | 600 |
| 895 | 900 | 900 |
Part 4: Brain Teaser Challenge
Monday (rounded): 200
Tuesday (rounded): 200
Total (about): 400 (200 + 200)