Rounding numbers: to the nearest ten and hundred
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What you will learn
By the end, you can round any whole number to the nearest ten and the nearest hundred, and explain why it rounds up or down.
Dev has 47 pence, but the bus fare is 50 pence. 47 is nearly 50, so Dev rounds it up and says “about 50”. Rounding swaps a messy number for the nearest tidy ten or hundred, so we can estimate quickly.
Read the explanation
To round a number, look at the digit one place to the right of the place you are rounding to. If that digit is 5 or more, round up. If it is 4 or less, round down and change the rest to zero. Rounding to the nearest ten looks at the ones digit; rounding to the nearest hundred looks at the tens digit.
- Digit 5 or more? Round up.
- Digit 4 or less? Round down.
- Nearest ten: look at the ones digit.
- Nearest hundred: look at the tens digit.