ok, thanks. Swedish pronounciation is really very difficult for me because it always change, depending on the words staying before or after, and some words are not pronounced at all. It's the first time I study a language with this kind of pronounciation. At the moment I'm studying Swedish only by Duolingo and Memrise and probably that's not enough, but for now pronounciation keeps on being very complicated for me. Anyway, thanks for your explanation! :)
Actually it's possible to write as varsomhelst too (it won't work in dictation exercises though, because of a bug), but the spelling as three words is more common and considered more correct. This goes to show how arbitrary the idea of "one word" can be.
Linguists say that some languages are "synthetic" and some are "analytic" – which basically means that some languages tend to make one word out of something where others tend to make several words out of it. This isn't an either/or category, it's more of a scale, but English is pretty "analytic" compared to most of the world's languages, and in general, more analytic than Swedish. For instance you say the book when we say boken. You say 'tin can', we say plåtburk. So as a general rule, if you translate a text between Swedish and English, you can expect to see a larger number of "words" in the English version. On the other hand, we have more particle verbs, like e.g. tycka om for 'like'. And some expressions, like var som helst can be made up of more words in Swedish than in English.
So tl;dr: different languages carve up things differently :)