Rounding is the method of taking a precise number and creating a shorter approximate value by rounding it to a particular decimal place.

The first step of rounding is to identify the place value to round and determine whether that number is closer to 9 than 0. If the number is closer to 9 increase the digit to the left by one. Then turn the place value into 0 and remove all the digits after it.

To demonstrate this, let's round 155.55 to the nearest tenth, one, ten and hundred:

- Tenth: 155.6
- One: 156
- Ten: 160
- Hundred: 200

The larger the decimal place we round to the easier the number is to read, however, more accuracy is sacrificed each time.

If you don't want to manually round numbers you can use this calculator instead, which allows you to round non-integer and integer numbers to the nearest decimal place ranging from billionths to billions.