Åk 6–9
 
English
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.