Åk 6–9
2.7  Writing and Reading a Number
Numbers can not only be expressed with digits but we can even write them in words.  When we talk to each other it would be difficult just saying the digits to each other if were discussing a number. When we express a number in words, we use the position system.  In section 2.4 the position system is described.

It’s not always completely logical when we put words to numbers.

In order to give a name to a larger number, we first give the number of millions and then how many thousands and so on.  Numbers larger than 999, the digits are often grouped in threes.  Numbers under thousand are written together!  Here are some examples: