In the 40's ? - How about the 60's! and early 70's. Not until computers
and calculators were able and willing to go above a slide rule ability.

We always did approximations and had some basic rules that allowed
truncation
or adding another variable ...

Martin [ who was in the workplace for several years when he bought a $600
4 banger
with memory, 12 digits and up to 4 of them below the decimal. I did log
and trig
by approximation routines. Some of which came out in EDN or Electronics
during the time.

Then TI and HP began to make calculators.

Martin



Anyone remember the mechanical calculators made by Singer Sewing Machine
Company. If you divided by zero, the only way to stop them was to unplug
them.