You probably can't remember anyone's phone number at this point, but your KID should memorize at least two. And here's how to teach them . . .
Someone did a video on how to teach little kids how to dial 9-1-1 without ACTUALLY calling 9-1-1 . . . and also how to dial YOUR number in case they ever need to.
The easiest way to do it is to make it a game with Post-It Notes.
Put 12 Post-Its on the wall, and write a number on each one, so it looks like the keypad on a phone.
Then, tape two pieces of paper to the wall above it: One should say "9-1-1" for emergencies . . . and the other should be your own phone number.
If you just leave the Post-Its up for a while, they'll eventually memorize both numbers on their own.
It's even easier to make them remember your number if you teach them to sing the last seven digits to the tune of the song "867-5309".