Helibegins
Not sure how bad your number /mathematical problem is? A lot is being given pressure settings and frequency changes which are all numbers.
You need to be able to remember those and read them back correctly.
Whether writing them down and getting into a habit of doing so would help?
If you cannot even write numbers down correctly you do have a problem.
I have always been terrible with names and often cannot remember the names of people I know reasonably well but numbers stick like glue.
Again whether there are number exercises you can do to improve this part of your memory maybe see someone who specializes in the condition?
It really depends how far you want to go? If its basic VFR for a tootle around the local area it should not be too much of a problem if its to go into commercial flying it would be.
My instincts are to find someone who knows and understands the condition who can give you exercises to improve things for you even coping strategies where you replace numbers with visual objects which you can remember.
I am only guessing but I am sure there must be some mind training methods for your condition.
Pace