Could someone please explain what is happening here? Isn't / used for divide and not %? What does % mean? I think I misunderstood the kata in that case, since I was trying to multiply and wasn't passing the right arguments. But when I tried it the other way around (dividing) nothing worked for the kata, so now I checked solution and people are using %. Guess I have to look that up... Not having English as my native language sure didn't help :)

Yes, it definately should. I had a real annoying time trying to finish the kata since it said nothing about case sensitivity in the description... spent a long time wondering if my regex was off or not.