Rounding numbers
Rounding is a way of making numbers simpler. E.g. by rounding 1783645 to thousands we get 1784000 what is a much nicer number.
When rounding we have to keep some rules. At first, we decide which is the last digit to keep.
For rounding to tens, it is the second digit from the right, for hundreds the third one, for thousands the fourth one, for ten thousands the fifth one, etc.
If this digit is followed by:
- 0, 1, 2, 3, or 4 - keep the same digit (we call this rounding down)
- 5, 6, 7, 8, or 9 - round the number up
Examples:
Round 183 to the nearest ten. The tens place is the second digit from the right (8) which is followed by the digit 3. Keep 8 in the tens place. The result is 180
Round 185 to the nearest ten. The second digit from the right (8) is followed by 5. Round up (increase 8 by 1 to 9). The result is 190
Round 1239 to the nearest hundred. The hundreds place is the third digit from the right (2) which is followed by the digit 3. Keep 2 in the hundreds place. The result is 1200
Round 1271 to the nearest hundred. The third digit from the right (2) is followed by 7. Increase 2 by 1 to 3. The result is 1300
Round 1496 to the nearest ten. The second digit from the right (9) is followed by 6. Round up (9+1=10). The result is 1500
Round 1496 to the nearest hundred. The third digit from the right (4) is followed by 9. Round up (4+1=5). The result is again 1500
Round 1496 to the nearest thousand. The fourth digit from the right (1) is followed by 4. Keep 1. The result is 1000
Round 21501 to the nearest thousand. The fourth digit from the right (1) is followed by 5. Round up (1+1=2). The result is 22000
