Times tables were drilled into me by the Domican nuns. At my advanced age, I’m still pretty fast. As for no calculators or computers to aid in multiplication, I still can use my slide rule with good speed. Admittedly, it can’t be used for ALL multiplication and division, but it works.
BTW, does anyone still have theirs. Mine is a Sun Hemmi for Chemical Engineers (back side has atomic weights and numbers, plus temperature and pressure conversion scales. No log functions). Bought it in Hong Kong for $5; cost in US was $16 back in 1960.
No, I need more than three significant digits.
Still have my Dad’s log log decitrig and my shorty K&E from 1963.