I do remember that if you didn't have a Pi key (I didn't!), you could always generate it by dividing 355 by 113.
It was easy to remember because it was just the first three odd numbers duplicated:
113355
Split it in the middle
113 355
and divide the bigger number by the smaller and you get
3.1415929203539823008849557522124
I always thought it was 22/7. Though 355/113 is certainly a lot more accurate for estimating pi.
I guess I was part of the younger generation the teachers all thought was too stupid to remember clever mnemonics like that.
























