Math practice · reimagined
Rounding Numbers Game
This rounding game asks for the nearest ten or the nearest hundred of numbers from 11 to 989, so an answer can drop to 0 or climb to 1000. Snap to the right round number before your rival does, and your fighter throws the punch.
Ages 4–99+ · no download · plays in your browser · 23 languages
What is rounding in math?
Rounding swaps an exact number for a nearby round one, such as a whole ten or a whole hundred, that is easier to say and work with. A book with 291 pages has about 290 pages, or about 300 if you round to the nearest hundred. The sign ≈ means “is about”, so 291 ≈ 290.
Every level of Rounding
Example: 296 to the nearest ten
- The whole tens on either side of 296 are 290 and 300.
- 296 is 6 more than 290 but only 4 less than 300, so it sits closer to 300.
- Rounding up adds one ten: 29 tens become 30 tens, which is exactly 300.
- So 296 rounds to 300, and 300 is what you type.
Learn it step by step
Rounding is how you trade a bit of exactness for a number that is easier to carry around in your head.
Picture the number line as a road with signposts every ten. 47 sits between the 40 sign and the 50 sign, and it is closer to 50 — so rounded to the nearest ten, 47 becomes 50. 43 is closer to 40, so it becomes 40.
The only awkward case is landing exactly halfway, like 45. Everyone needs to agree what to do, so the rule is: halfway rounds UP. 45 becomes 50.
Rounding to the nearest hundred works the same way with bigger signposts: 472 sits between 400 and 500, closer to 500.
Decide which signpost is nearer, and type that number.
Tips and common mistakes
- Look only at the digit just right of the place you round to: 0 to 4 keeps the lower round number, and 5 to 9 moves up to the next.
- When rounding to the nearest hundred, ignore the ones. The 9 in 649 tempts many children to round up, but the tens digit is 4, so it becomes 600.
- Open a book at any page and round the page number to the nearest ten, then to the nearest hundred. Take turns choosing the page and checking each other.
How to play
Every problem pairs a number with a target, such as 612 to the nearest ten. The target flips between ten and hundred at random, so read to the end. Type the round number on the keypad: if yours lands first, Tomato strikes, and a quick answer does more damage than a slow one.
— Quick answers —
Rounding: the short FAQ
- What does round to the nearest ten mean?
- To round to the nearest ten means to replace a number with the closest number that ends in 0. 291 lies between 290 and 300 and is only 1 away from 290, so it rounds to 290. In the same way, 612 rounds to 610 and 588 rounds to 590. A rounded number like this is quicker to add, compare and remember.
- How do you round to the nearest hundred?
- To round to the nearest hundred, look at the tens digit. If it is 0 to 4, keep the hundreds digit and put two zeros after it, so 721 becomes 700. If it is 5 to 9, raise the hundreds digit by one, so 861 becomes 900. Numbers below 50 round down to 0, and numbers from 950 to 999 round up to 1000.
- Is there a quick way to check a rounded number?
- Two checks catch most slips. First, the answer must be a whole ten or a whole hundred, whichever was asked for. Second, it can never land far from the start: at most 5 away when rounding to tens, and at most 50 away for hundreds. If 638 becomes 700, the gap of 62 gives the mistake away.
- Why does my child keep getting rounding wrong?
- Often the cause is rounding in two steps. Rounded to the nearest ten, 448 becomes 450, and if your child then rounds 450 to the nearest hundred, they get 500. But 448 is closer to 400, and 400 is the right answer. Ask them to always go back to the original number and look at just one digit.
- Is this rounding game free, and can a teacher use it with a class?
- Yes, it is free and runs in a browser tab, with no account and nothing to install. For rounding practice with the whole class, write 563 on the board. Ask half the room for the nearest ten and the other half for the nearest hundred, then discuss why 560 and 600 both fit. Then pupils fight on tablets. The schools plan, priced per student, adds a teacher dashboard that shows who is improving.