I learnt all the techniques and tricks instructing on the C-5
Same here but as a FO on the 727, before the days of
computer games and FMCs.
Provided the box is loaded correctly and you're aware of
your weight and prevailing w/c, the A320/1 Frogmobile
gives a handy DTG readout at the bottom of the F-PLN. I
use it quite a lot esp when on oblique radar headings etc
on descent. The kids are usually glued to the Progress and
yelling if the box thinks I'm too high or low. That 'c' (the
hypotenuse) is of a shorter distance than 'a' + 'b' seems
to escape or confuse them.