Stop in for a cup of coffee
I just won an ebay auction for a calculator like I had back when I was in college... HP 15C.... They are different to use than standard calculators, but once you get the hang of them, they are much easier.... They use reverse polish notation and you can stack up to 4 numbers at a time... Programmable, and you can store numbers in the different registers.... I have to review how to use it again, and bought an owners manual for it also....
They cost more now than they did back then...
They also came out with a second run of Limited Edition ones, but they don't have the original Saturn processor and the buttons don't feel as firm as the originals... This is one of the original editions, the good one....