Setting out answers

[:)]

Just wondering for answers such as 0.0051 mol, should we leave answers like that or 5.10 x 10^-3?
The answers in textbooks put them in 5.10 x 10^-3 form, does it matter if we leave it as 0.0051?
Thanks!

[shinny]

I prefer writing in scientific notation as it's less prone to errors, but you won't be marked wrong if you write down all the zeros. However, doing so is quite prone to errors.