I used to do an approximation of the result on paper to get the decimal point right.
which is why all us olde phart engineers have difficulty with the youngsters who believe their computer output garbage without doing a back of a fag packet sanity check rough calc ...
Slide rule I think
I can't recall a single occasion where my slide rule stopped working because of battery problems ... and, for many calculations, its accuracy is just as practical as the 495 irrelevant decimals which the computer spits out.
stressmerchant, I'm with you good sir.
Even in more recent times old techniques die hard. Jess Smith, who was the force behind the short lived MAMBA single in Melbourne started the design in chalk on his hangar floor ..