Thanks for the replies.. that is what I thought, but then D(not currently)H said the same (as the maths teacher) and that we should be using the modern Mega, tera, peta (teacher never mentioned those, just DH)... but they are prefixes aren't they? DS knows numbers up to Decillion... just general knowledge to that level I know, but if he should be learning another set of names it would be good to know. Maybe I can find some way to use quadrillion at our upcoming parent/teacher meeting to see what he says:-)
It may sound like I am making light of this, but DS was told in front of the class that the word didn't exist, which has made him believe his teacher is not too bright, so if there is another modern way to describe numbers and to stop DS thinking DT is stupid then it would be appreciated
Quadrillion is a real word (google and wikepedia can quickly settle any argument these days!). So the teacher was wrong.
I don't think its a word which is widely used in practice though. When talking about big numbers scientists would tend to use "10 to the power of 15". Those with less understanding of powers of 10 would probably say a thousand trillion. Googol and Googolplex are the only big number words above a trillion which are commonly used.
Mega/giga/tera are prefixes which are applied to metric units. They're similar to kilo. These are used for things like bytes when talking about computer storage but for some reason aren't used for things like distance and mass. (people would generally say the distance from London to New York was around 5000 kilometres rather than 5 megametres!)