This is the calculator that got me through junior high and high school. It even handles fractions, which is what you see on the display there.
355/113 is a very close approximation of PI, accurate to 6 decimal places.
Yes the calculator also has a proper constant for PI, but 355/113 is a pretty nifty trick in it of itself.
355/113 = 3.14159292, at least on this calculator.
Did you know that the most complex calculation I tried on that calculator is 69!
Yes, 69 factorial ... !
It ends up taking like 2 or three seconds for it's little solar powered CPU to process, but it basically verifies the CPU is working right.
Edit: Still sucks to have a dead button..