I did this too! Not on a notepad, but on a Royal typewriter, age 10. My dad had a telecommunications consulting business, based on a remote Univac mainframe he rented time on. He'd bring his Texas Instruments Silent 700 printer-terminal home from work, and I'd sometimes get to play Adventure and what-not if he wasn't using it. I vividly remember typing my first BASIC program on the typewriter, one afternoon after school, and then waiting excitedly for him to get home so I could actually type the program into the terminal. (Pretty sure the program was: 10 PRINT "HELLO" / 20 GOTO 10.)

EDIT: This would have been ~1976.

I did that too. I thought it was common. I learned programming by reading my older sister's Computer Science manual from high school in preparation for me starting high school (2004, Romania).

All school work was on paper so it was a necessity.

But it was fun too. In pointless classes like French, there was nothing better to do. It was worthwhile to work on my personal programs on paper and type them out when I got home.

You had to think about the approach before starting to write it down. I would leave a lot of vertical space in case I needed to put something above. In some cases I would write the code afterwards, draw a rectangle around it, and point to where it needed to move. It was a bit messy sometimes.

Adorable? Maybe. Probably also a little bit weird. But kids are like that, they can be a bit weird sometimes. Translating square paper pixel graphics to decimal numbers and writing them down is not everyone's idea of fun.

It was during the first home computer revolution. My library had books on the subject which were intriguing, including the legendary "BASIC Computer Games". Those were written for several different computers, which didn't matter since I didn't know anybody who had them. But soon several of my friends got C64s and we could rewrite them for those.

Which was fun. Maybe not a common pastime back then but not unheard of either. Kids love to experiment and this was just one way of doing that. But it was definitively programming. There's wasn't much else to do with a home computer apart from what few games you had access to.

This reminds me, there was magazines in the regular shops which contained source code listings of programs, including simple games with graphics declared as decimal constants. Before modems that was how many people got their software. Since you had to type them in by hand, it was very natural to make modifications.