# Decimal - Rounding off

### Concept

- Rounding is a way to simply a number so we can remember it easily. Sometimes you don’t really care where you have 3.7g of sugar, or 3.9g of sugar, or 4.0g. There are all almost the same, and it’s a lot easier to remember 4, than the other numbers.
- Rounding decimals works similar to rounding units, tens and hundreds.
- If it’s 5 or more, go up.
- If it’s 0 to 4, go low.

### Theory

First the basic rules of rounding:

- 3.1 => 3.0
- 3.4 => 3.0
- 3.5 => 4.0
- 3.9 => 4.0

Now for decimal rounding. Let’s round all the numbers which have 2 decimal places to 1 decimal place.

- 3.0
__4__=> 3.0 - 3.0
__5__=> 3.1 - 3.0
__9__=> 3.1

How about 3 decimal places to 2 decimal places:

- 3.00
*2*=> 3.00 - 3.04
*5*=> 3.04 - 3.05
*9*=> 3.06

### Common Misconceptions

- How should I round 0.5, it’s right in the middle?

### Quiz

Test your concept