Question: Decimal Places...

Sorry to bother you again. I want my computations(results) to carry/have more decimal places so that I can choose how many decimal places to show myself. This is because, my result is always displayed in 9 d.p but I want more decimal places to be displayed. Just like the way we change the way maple display matrix in-line with command interface(rtablesize= N), is there a similar way i can do the decimal place thing?

Secondly, how can i suppress the value A amd B from beign displayed everytime the loop written below runs. As an example,

for i from 1 to 5 do

    A := i:

    B := 2*i:

    C := A+B;

end do;

I only want the result C to be displayed each time the loop runs but A and B also displays despite ending their lines with a : and if I terminate the loop with end do:, nothing is displayed. Is there a way to overcome this?