Pi Approximation Day

[Gerson W. Barbosa]

(07-23-2022 03:18 PM)C.Ret Wrote:  Is this a specific HP-42S trick, does memory recall arithmetic modify the LAST register?

Yes, it does, unlike memory store arithmetic:

05 RCL ST Y (T 10 10 10)
06 RCL× ST Z (… 100)
07 RCL+ ST Z (… 110)
08 RCL× ST X (… 12100)
09 RCL× ST L (… 1331000)