stupidly easy hw that I need help with

[nilamo]

(tippy/100) 

Because you're using python2, and because tippy is an int, if you do any calculations, you'll still have an int (the decimal part is ignored).  So 10 / 100 is 0, not the 0.1 you expect.  Instead, divide by 100.0, so python switches to a float, so the decimal value is kept.

That's more complicated than it needs to be, and that's not how it works in python3.