What numbers did you memorize as a kid? How old where you? And why?

I didn't memorise numbers much that I can recall.
But I recall it started about grade 1, so about 5, lying in bed in the dark and counting 1,2,3... and I realised I could keep counting. The odd thing was I could see them stretching ahead of me visually. When I got to 200 they turned left. I knew a thousand was over on that side because then it turned and went away from me again. All numbers exist in a particular physical space around me and I never thought about it.
Over time I could see the calendar in a circle around me, like a clock, with the months and the days, with December 31/ Jan 1 directly in front and 30 june behind me.
Weeks a different pattern. Dates a complex pattern.
I thought it was normal. I didn't know until middle aged and saw a documentary that i had synesthesia.

I had my phone number and address memorized when i was very little.
We lived in the way out and had pretty free rein. I reckon mom wanted us returned if we wandered too far.
I still remember it to this day.

Growing up it was Telephone numbers and Birthdays, because who has time to look up numbers in a phone book and I wanted people to feel special by making effort to remember their birthday and wish them.

Phone numbers came easily to me. I knew everyone’s number off by heart. Since I got a cell phone , I don’t know anyone’s number

I can't remember any except our mailbox number at the post office. From 5 until I left home, I lived in a tiny town and addresses weren't necessary. Everyone knew exactly where everyone else lived.

I was bribed w money to memorize my times tables at age 8.

Times tables, lol. Also our address. Some phone numbers. Birthdays too.

5, 10, 15, 20, 25, 30, 35, 40, 4, 50, 55, 60, 65, 70, 75, 8, 85, 90, 95, 100.... was terrible at memorising numbers XD

Phone numbers, piano finger placements

None. Heart doesn't need brain in such cases.

Anything important that I didn't write down.

I remembered my address and my phone number, as well as the birthdays of every family member. In SF some supervisor had the bright idea of requiring young school children to wear dog tags with their addresses and blood types, in case they were in accidents. I still have mine somewhere. Definitely a different time.

I remember being 4 and learning my address and phone number and that my parents names weren't Mommy and Daddy. My 4-digit phone number (before dial phones in my small hometown) is now part of my email address.