I have extreme issues doing any sort of math in my head and have been like this since birth - I failed a general level math course in high school. I can't add

I have extreme issues doing any sort of math in my head and have been like this since birth - I failed a general level math course in high school. I can't add 2 two-digit numbers in my head at all, forget multiplication. However, I understand compound interest and consumer debt very well - I pay my credit card in full every month, I save for retirement, I actively budget. I've also had a career in the computer and Internet business for 25 years. A calculator solves a lot of problems.