Also, my difficulty with numpy isn't applying functions to arrays, it's seeing __repr__ of a multi-dimensional arrays and grokking what it's showing me.
Site worked well on both my iphone and pc btw.
I'd like to more clearly show the answers / I originally didn't show what the test inputs (e.g. if square root is tested with 25, 9, and 4) so you couldn't just return 5 if 25, 3 if 9, etc... but I could display some of the test inputs and not all of them.
It definitely would be great to show the intermediate results of the calculations and for things like matrix multiplication `a.dot(b)` isn't very complicated, but it doesn't give you intuition on what's happening under the hood.
Thanks for the iPhone feedback — I tried my best to make sure it worked well on mobile. The few examples I could find of interactive Python tutorials usually involved spinning up a VM with multi-second lag for each question and textareas which were not at all mobile-optimized so I wanted to try and do something better :-).