[Elsie]

 

If all failed; an HP-45 calculator could handle all the computin' needed.

 

 

https://books.google.com/books?id=-aM5DwAAQBAJ&pg=PA117&lpg=PA117&dq=Apollo+astronauts+hp-45+backup&source=bl&ots=Xd1c7gX5-_&sig=ACfU3U2z5sNzZvyyntCw9n_FPi0p6XqEwQ&hl=en&sa=X&ved=2ahUKEwjhkZ3Ov8PpAhX8B50JHevcDNsQ6AEwGXoECAoQAQ#v=onepage&q=Apollo%20astronauts%20hp-45%20backup&f=false

 

 

 

Was it in Polish or Reverse Polish notation??

[reg45]

I’ve had HP calculators since the HP-25. I still have my HP-48SX (and it still works) although I am more likely to use the HP-48 emulator app on my iPhone these days.

Oh, by the way it’s Reverse Polish Notation since you enter the operator after the operand.