Because outside of a very narrow set of high performace situations, it doesn't matter at all. Even the cheapest embedded computer can do this in nanoseconds. And treating it like strings is more intuitive since the problem cares about them more like strings than numbers.

The to_s is redundant I think. to_s is automatically run on items inside #{}

Just wow..

I'd reject this so fast in production code but it works technically.

I did this in C and had the same issue. Turned out my math was coming out wrong but it still passed the inital tests. Use printf to check your results againt wolfram and see what happens.

Exploit!! ahahah

This is what I love about Ruby compared to most languages...it has loads of built in functions as standard. I disabled the .even but if @MichaelSel (the author of the kata) is happy then .odd can be disabled too.

Yep;) Sounds like a true))

This feels like it shouldn't be allowed :P

This was made intentionally complex wasn't it?