I'm not *that* old, doggone it. But even over my time things have changed so much with the way things are done mathematically and otherwise, I have to wonder what most people would do without calculators and canned software.
Then again I went to engineering school, so what I thought of as normal turned out to be unrealistic for most people. Sheesh, a couple of days ago I told someone what the sine of a certain angle was off the top of my head and you would have thought I'd performed a miracle.
Even technical people are deteriorating because calculators are inescapable. Can you still do math in your head? If you want to see where you stand with impromptu mental calculation, try this. How did you do?
And then there are simple graphical constructions. Do people still know how to use a straightedge and compasses nowadays? I haven't talked into any newly minted engineers lately, but it wouldn't surprise me if they knew much about how engineering graphics were produced before the CAD era.
Or would they even know what a nomogram is? And slide rules - we don't even speak of slide rule calculators any more. But surely they still use Moody diagrams and psychrometric charts.
Nomograms and lots more are to be found at Dead Reckonings - Lost Art in the Mathematical Sciences, which is such a great find I have no idea what to link in particular.