How many groups of thousands are in 90000?

Answer 1

There are 90 thousands here. Never heard them called groups so I'm not sure what you mean by the term. In a pile of 90000 objects there is a stupifyingly large number of ways of picking up 1000 of them. 90000 ways of picking up the first x 89999 ways of picking up the second x .... unless they are all identical etc etc.