Rounding Numbers

A rounded number has about the same value as the number you start with, but it is less exact.

For example, 341 rounded to the nearest hundred is 300. That is because 341 is closer in value to 300 than to 400. When rounding off to the nearest dollar, $1.89 becomes $2.00, because $1.89 is closer to $2.00 than to $1.00

Rules for Rounding

Here’s the general rule for rounding:

If the number you are rounding is followed by 5, 6, 7, 8, or 9, round the number up. Example: 38 rounded to the nearest ten is 401

If the number you are rounding is followed by 0, 1, 2, 3, or 4, round the number down. Example: 33 rounded to the nearest ten is 30

What Are You Rounding to?

When rounding a number, you first need to ask: what are you rounding it to? Numbers can be rounded to the nearest ten, the nearest hundred, the nearest thousand, and so on.

Consider the number 4,827.

4,827 rounded to the nearest ten is 4,830

4,827 rounded to the nearest hundred is 4,800

4,827 rounded to the nearest thousand is 5,000

All the numbers to the right of the place you are rounding to become zeros. Here are some more examples:

34 rounded to the nearest ten is 30

6,809 rounded to the nearest hundred is 6,800

1,951 rounded to the nearest thousand is 2,000

In your maths books round these numbers to the nearest 10

12,44,59,56,77,39,37,21,32,55,68,83,91,52,78,88

Round these numbers to the nearest 100

99, 234, 674, 889, 455, 239, 588, 341, 774, 178, 499, 451, 673

Round these numbers to the nearest 1,000

5,999, 3,501, 8,456, 3,555, 9,999, 3,499, 7,245, 4,522, 8,999, 3,567

Round these numbers to the nearest 10,000

56,999, 43,455, 72,899, 23,645, 34,001, 56,767, 98,999, 21,534

Now you can play these games:

http://www.math-play.com/Rounding-Numbers-Pirate-Game.html

http://www.softschools.com/math/rounding/game/