The hint about 15 lines makes people turn their code into kind of fastfood. Not nutricious :) I'd suggest to respect C# more than that. Anyway, thanks!

C#: if this kata concerns coder's awareness it worths 5 kyu. If usage of library evaluation functions is prohibited it is 2 kyu. Big-big request to the authors: make yourselves plain both in task's description and testcases. I appreciated the second option (without language built-in evaluation) very much still :))

This kata sets too much accent on adapting output to the test result template for my like. I wouldn't mind the division result being numeric or floating-point in real life.

Hoogle seems not to know about Data.List.Split, and I failed to find something like splitOn. Thanks for the hint!

That did the trick. Thanks!

False positive in case of
isOpposite "ab" "CD"

Very good solution! I'd wish to append a template
match _ ys = ys

unwords is [String] -> String, how come it compiles [(Int, String)] back to String??