Åk 6–9
6.2 Prefixes 
Mathematicians are lazy.  Instead of expressing long numbers and words, they have come up with abbreviations.  You use these abbreviations daily without thinking about it. 

An example is:

”It is four kilometers to the bus station”.
Here the prefix kilo, which is abbreviated as k, means thousands.  In this case, “4 km = 4,000 m” to the bus station.
Four kilometers = Four thousand meters
4 km = 4 · 1,000 m = 4,000 m

Several examples of prefixes can be found in today’s technical world where you for example express a computer’s memory capacity in terms of bytes.  Here the development has gone quickly forward. 

A normal text file on a computer can be for example 4 kb = 4 kilobytes = 4,000 bytes (it isn’t exactly 4,000 but 4,096 but is rounded off) and a music file with a normal sized song is 4 Mb = 4 megabytes = 4,000,000 bytes (4,194,304 bytes).

”My mp3-player has a memory capacity of two gigabytes.”


Foto: Ryan Stonn

Giga, which is abbreviated as G, is equivalent to one billion.  In this case, the memory capacity is 2 Gb = 2,000,000,000 (2,147,483,648 bytes)

Two gigabytes = Two millions bytes
2 Gb = 2,000,000,000 b

Here is a table for some of the most common prefixes.