Ah! Thanks, I was really struggling with how to implement all the numbers and operators without copy pasta. "define_method" is exactly what I wanted.

This makes a lot more sense. I was struggling to understand that my problems were coming from using string. As soon as I saw the integer conversion it all made sense. Thanks!

I really appreciate this solution, thanks for posting it. Learning elegance from solutions like these is the primary way I'm learning from this site.

I really love this code, it's a really clever way to avoid all the problems with detecting what's a letter or not, thanks!

I feel like this is ridiculously easy in Ruby, but maybe not other languages? Anyway, array diffs is a neat function Ruby provides. Nice solution!

Thanks for putting this up, I "solved" the kata, but this helped me actually understand it algorithmically. Thanks!