I think - but I could be wrong - that if you follow the instructions and do operations in correct order you can work with integers only and there is no rounding problems.

Nothing wrong if you follow the instructions.

I'm getting the same as everyone... random testing fails for whatever reason... Have to keep hitting Submit until Kata passes or else will just skip this altogether... :/

There's a typo in the description which says "an valid array" where it should say "a valid array". Other than that, nice kata. It could have a few more contraints though!