Richard Coke wrote:

Being inherently lazy and
concerned with entry errors, I try to simplify things before crunching
numbers (and by using an RPN calculator, of course).

I must be lazier than you. I don't like to have to simplify things or worry
about entry errors so I use an AE calculator, of course. G

Being even lazier, I match your AE and raise you an APL. :-)
(+/80 50 69÷3)(+/80 90÷2)+.x.60 .40
73.8

Ted