I'm hoping someone can clear this up. I'm wondering what the difference is between: "Ich mag schlafe nicht" and "Ich schlafe nicht gerne". Is it translatable like this?
"I do not like sleep [as a concept]" > "Ich mag schlafe nicht".
"I do not like sleep [as an activity]" > "Ich schlafe nicht gerne"
I think that would have to be "Ich nicht schlafe gerne" for that. I looked up a page about negation, it helps. http://www.lsa.umich.edu/german/hmr/101/Mehr_Vorsprung_Grammatik/Kapitel_2.html
I don't sleep well is a much more common phrase in English than the Duolingo provided alternative I don't sleep gladly. [And therefore I can understand how easy it is to type I don't sleep well here.] Unfortunately [for those whose minds said this must be what it means], it simply isn't what was expected.
[Edits in square brackets, for clarity. I agree, and always did, with TrioLinguist that nicht gut is a closer translation for not well.]
Actually that would be wrong. Gerne does not really mean gladly here, it is used to say you like an activity. Ich schlafe gerne means I like sleeping, Ich schlafe nicht gerne means I do not like sleeping.
Ich bin kein Experte... But I think I do not sleep well (or gladly if you want) would be Ich schlafe nicht gut.