Prefixes are used to simplify the writing of very big or very small numbers.

For instance, instead of having to write 12 500 000 m every time, you can simplify it by using the prefix mega (M), hence it can also be written as 12.5 Mm. Similarly, 0.00054 s can be written as 0.54 ms.

If you are unsure or confused with the unit conversions, you can refer to the following videos.

**1) Prefixes can be used for different physical quantities units.**

**2) Unit conversion with examples**

**3) Unit conversion for units of area and volume**

**4) Unit conversion for units of speed and density**