Hmm this bug:
12514 [Maemo 5 Community SSU] Calculator program, percentage operations
Does not seams to be solved fully.
The bug states that if you type 100-10% the outcome should be 90 but the resalut you get is 99.
That seams to be fixed with the update on osso-calculator.
But I tryed 1000-10%, that I expect to be =900, but I endup with 990 instead.
Im not that good math, but I guess 1000-10%=990 is wrong.