Rounding Numbers
Grade 4 · Math · Study Guide
Learn how to round whole numbers to the nearest ten, hundred, and thousand.
Rounding means replacing a number with a nearby number that is easier to work with. It's something you use all the time in real life — when you estimate prices at a store, or figure out roughly how far something is.
The rounding rule is simple: look at the digit to the right of the place you're rounding to. If that digit is 5 or more, round up. If it's 4 or less, round down (keep the digit the same). For example, to round 347 to the nearest hundred, look at the tens digit: it's 4. Since 4 is less than 5, round down — 347 rounds to 300.
To round 368 to the nearest hundred, look at the tens digit: it's 6. Since 6 is 5 or more, round up — 368 rounds to 400. Notice that rounding up sometimes changes more than one digit.
You can round to any place. To round 5,839 to the nearest thousand, look at the hundreds digit: 8. Since 8 ≥ 5, round up to 6,000. Rounding is one of the most useful math skills you'll ever learn — it lets you make quick estimates and catch mistakes.
| Number | Round to Nearest... | Answer |
|---|---|---|
| 347 | Hundred | 300 |
| 368 | Hundred | 400 |
| 5,839 | Thousand | 6,000 |
| 2,450 | Thousand | 2,000 |
| 82 | Ten | 80 |
Key terms
- Rounding
- Replacing a number with a close approximate value.
- Round up
- Increase the digit in the target place by 1 when the next digit is 5 or more.
- Round down
- Keep the digit in the target place the same when the next digit is 4 or less.
- Estimate
- A reasonable guess about an amount, often made using rounded numbers.
Flashcards
- Rounding rule
- Look at the next digit. If it is 5 or more, round up. If it is 4 or less, round down.
- Round 347 to nearest hundred
- 300 (tens digit is 4, so round down)
- Round 368 to nearest hundred
- 400 (tens digit is 6, so round up)
- Round 5,839 to nearest thousand
- 6,000 (hundreds digit is 8, so round up)
- Estimate
- A close but not exact answer, often found by rounding first.
- Round 82 to nearest ten
- 80 (ones digit is 2, so round down)
Practice questions
What is 473 rounded to the nearest hundred?
- 400
- 470
- 500
- 480
Show answer
Answer: 400
To round 473 to the nearest hundred, look at the tens digit: 7. Since 7 ≥ 5, round up. 473 → 500. Wait — 473: hundreds digit is 4, tens digit is 7 ≥ 5, so round up to 500.
2,650 rounded to the nearest thousand is 3,000.
Show answer
Answer: True
2,650 rounded to nearest thousand: look at hundreds digit, which is 6. Since 6 ≥ 5, round up to 3,000.
The rule for rounding says: if the next digit is 5 or more, round ___.
Show answer
Answer: up
The rounding rule: digits 5–9 mean round up; digits 0–4 mean round down (stay).
What is 8,349 rounded to the nearest thousand?
- 8,000
- 8,300
- 8,400
- 9,000
Show answer
Answer: 8,000
8,349 rounded to nearest thousand: look at hundreds digit, 3. Since 3 < 5, round down. 8,349 → 8,000.
64 rounded to the nearest ten is ___.
Show answer
Answer: 60
64 rounded to nearest ten: ones digit is 4 < 5, so round down. 64 → 60.
Fun facts
- When NASA calculates rocket trajectories, they use precise numbers — but engineers always round for quick mental checks!
- The number line is the best tool for understanding rounding — which end is the number closer to?
Get a personalized course on Rounding Numbers built around your child.