I'm not sure you need to memorize the tables to do multiplication in your head. The 10s are a freebie, and the 2s can be done by most people without much effor

I'm not sure you need to memorize the tables to do multiplication in your head. The 10s are a freebie, and the 2s can be done by most people without much effort, for numbers under 100. 5s are just half of the 10s. 9s are just 10x - 1x. 11s are adorable. I'd wager most people internalize little tricks like these for all the multiples of single digit numbers and the lower double digits. Of course, if you do math in your head all the time, eventually you memorize frequent combinations. Anybody who can trivially multiply high doubles digits or 3 digit numbers in their head is exceptional.