What else can I do with 0.9 x 10^16

this answer was from the this question:

(300,00)(15,000,000)
-----------------------------
0.0005

What do you want to do with it ? It is a simple, straightforward number, which does not need anything doing with it. (Except, very possibly, putting it into "standard form", which means that the first part should preferably be a number between 1 and 10 : 9.0 x 10^15. But really, it is fine as it is. Only a real stickler would object to the form you write it in.)