Round to three decimal placesWhat is rounding and why do we do it?

You might not always need or be able to give an exact answer to a calculation, Sometimes an approximate answer is good enough. You can give an approximate number by rounding up or down.

Part ofMathsEstimation and rounding

What is rounding and why do we do it?

  • Rounding a number means changing a number to a similar amount in order to make it simpler. This can make it easier to calculate with or use in everyday life.
A measureing jug

Example 1

You might decide to round 365ml down to 350ml when measuring water for a recipe.

A measureing jug

Example 2

This calculation might seem difficult:

5.497586986976 x 2

By rounding the long number to 5.5 the (approximate) answer feels simpler to work out:

5.5 x 2

Next page
Rounding to 3 decimal places (3 d.p)