Numbers that are multiples of 10, 100 or 1 000 are sometimes called round numbers.

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We may choose to 'round off' a number to the nearest round number, to give us a number that is easier to work with.

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Rounding a number to the nearest ten means finding the multiple of 10 that is nearest to that number.

  

A useful way to visualise this is to think of a row of numbered houses. Some of the houses are multiples of 10 (10, 20, 30, etc.) and all of the other houses are between two multiples of 10.

 

For example, 144 is between 140 and 150, but nearer to 140. So 144 rounded to the nearest ten is 140.

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Rounding a number to the nearest hundred means finding the multiple of 100 that is nearest to that number.

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For example, 298 is between 200 and 300, but nearer to 300. So 298 rounded to the nearest hundred is 300.

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