For a century up to the 1970s most engineering calculations were done to three decimal digits with implied-exponent floating point hardware¹. ¹ https://en.wiki

For a century up to the 1970s most engineering calculations were done to three decimal digits with implied-exponent floating point hardware¹. ¹ https://en.wikipedia.org/wiki/Slide_rule https://en.wikipedia.org/wiki/Slide_rule