You have the entire Internet full of knowledge and teachers at your disposal. Use it. If you forgot how to do arithmetic it's probably because you haven't used it for the past few years. Go on Khanacademy or watch YouTube or use Google and watch lessons revolving around arithmetic to help refresh your brain on the matter. I guarantee you that in a few hours, like
>>12964644 said, you will know how to do arithmetic again.
Don't be so hard on yourself OP. It'll be okay.
