I have dyscalculia too
@iVibe. I don't mess up change since I think of it in terms of something tangible (Like I have to give them 1 five, 3 dollar bills, 2 quarters, a nickle and a penny instead of thinking I have to give them $8.56). It causes me to switch numbers around or mistake one number for another but I correct myself pretty quickly or play it off like "Oh, it's loud, you must've heard me wrong!" It's only when a) I type in the wrong amount or b) guests start shoving handfuls of change in my face demanding I give them only singles after I already put in the amount that I get fucked up, at which point I a) do a wrong payment, apologize and tell them it's the rules, or b) tell them we can't accept change after the transaction is done, and they're SOL because I purposefully repeat the amount they give me "Out of $X?" in case the guest wants to hold up my line for 5 minutes looking for 67 cents in change.