Help me choose next calculator

[ttw]

Speaking of older. I did computing when the only calculators were the Friden 10-digit calculators (both hand-cranked and electric.) I was taught (in grad school when I first saw a computer) to run small cases on a calculator to understand all the steps. Then put the computation on a computer (different language and numerical properties) and see if the same results were obtained. Then run the big stuff.

I still do so only I've got an HP50g to replace the Friden.