I’m like that with some multiplications but not all. Especially the ones I could never remember, and that I consequently studied extra hard, are indelibly burned into my brain. Ask me what 7 times 8 is and I will immediately answer 56. It’s not even the number that’s etched into my brain but the actual sentence I used all those years ago staring at the tables. I will “hear” siebenmalachtissechsundfuffzich (obviously the sentence is in German).
It’s the same with certain Latin declensions I had to learn by heart and which I will never forget because they are stuck in my brain as a sort of sped up poem with a very specific rhythm.
res
rei
rei
rem
re
res
rerum
rebus
res
rebus