Decimals in division

["Raul A. Jager W." <raul@xxxxxxxxxx>]

I tryed to calculate a discount using:

neto$ = imp$ / ( 1 + porciva /100);

where neto$ and imp$ are defined as 13, 2
I expected two decimals, but instead I got an integer value in neto$.

I found a "solution" using:

neto$ = %dec(imp$ / ( 1 + porciva /100): 13: 2);

Works fine, but looks more complicated than necesary.
Why the original eval did give me an integer?

TIA
Raúl