Gotta wonder how many of your readers know what a sliderule is - and how many fewer know how to use one. It's pretty easy to be off by an order of magnitude with one, so you'd also need to have the ability to come up with a general ballpark result in your head (or on the back of an envelope) to check against - and that was my problem. :-( Leading to my jump into digital computing early on. :-)

BTW/FWIW, I knew a couple of the guys who worked on the Apollo project. One was on the team that built the nav computer for the Lunar Lander (yes, the one that kept needing to be rebooted on the very first landing).