How can I expand e.g. number 1.*10^-8 so that there would be no exponents? It should look like 0.00000001.
Representation of numbers of handled with
NumberForm. Choice of exponent to display is determined by its
ExponentFunction option. If you never want an exponent displayed, this option should be a function that always returns Null, i.e.
NumberForm[1.*10^-8, ExponentFunction -> (Null &)] (* 0.00000001 *)