Hi Martina,

As David says your rules of rounding are a bit perverse.
To avoid arriving at that place, do your rounding at the start
of your calculations so that you don't arrive at awkward
results!

Following your logic I could make a case that a result of
52.26% eventually rounds to 100% and thus constitutes an A.

Please don't be offended by my remarks Martina, but the
precision you use has to be weighed up against the result you
are trying to achieve.

Sincerely
Martin