I remember in uni two days after taking an exam I dreamed about the professor asking me to explain the calculationd I made, and while I was going through them I

I remember in uni two days after taking an exam I dreamed about the professor asking me to explain the calculationd I made, and while I was going through them I realized at some point I did an addition instead of a subtraction. I woke up and indeed I made that mistake. (This was during covid so the exam was done remotely and I still had the paper with the calculations at home).