Rounding to the Nearest Ten

Rounding gives a number that is close but easier to work with.

Round means to swap a number for the nearest ten or hundred.

Every number sits between two tens

47 sits between 40 and 50. The question is which one it is closer to.

The halfway point decides

Halfway between 40 and 50 is 45. Past halfway rounds up, before halfway rounds down.

Exactly halfway

If a number lands exactly on halfway, like 45, we round up. That is the agreed rule.

Rounding replaces a number with a nearby friendly one

Rounding 67 to the nearest ten gives 70, because 67 sits between 60 and 70 and is closer to 70. You are deliberately giving up a little accuracy in exchange for a number that is much easier to work with. That trade is the entire purpose of rounding.

Use the number line, not the rule

Draw the two tens either side and mark your number between them. Which end is it nearer? That is the answer, and you never had to remember a rule. The digit rule you may have been taught is only a fast way of asking the same question.

The halfway case

65 is exactly the same distance from 60 as from 70, so the number line does not decide. Mathematicians agreed on a convention: round halfway cases up. So 65 rounds to 70. It is a choice, not a fact, made so that everyone gets the same answer.