"Bye!"

Translation: Hej då!

[ocasus]

Alt 134 for those wondering

[IamJustintime]

What does då mean exactly?

[ssoonjnjaa]

It means "then"

[LonnekeBak]

Voor de nederlanders hier, lijkt op houdoe (doei in brabants)

[panquemad0l]

Hi bye?? How does that make sense xD

[gapes]

Maybe more of a "Hi later" or "see you later"

[Zmrzlina]

Does it have to make sense?

[AuralArk1]

I thought the same thing

[VisaPollar]

Doesnt tjäna fit?

[Eurovision42]

I thought that another acceptable version of bye was "hej hej"

[Drufsen]

It's correct, but it's only used when speaking is certain situuations.

[Marshameus]

According to my Swedish friend it's only supposed to be one word: 'hejdå'

[Arnauti]

Your friend is somewhat wrong. Språkrådet recommends writing it apart and says that although the form hejdå is common in practice, it's still only considered an informal version.
http://www.spraknamnden.se/fragor/arkiv_sprakrad_05.htm#hejda
Both versions are accepted answers here though :)

[deactivated user]

"Hej" and "då" should NOT be apart, at least in Skania it's like that.
Since my childhood I've always said "Hejdå", but I'm still confused on why Duolingo said "Hej då". I didn't get incorrect, instead Correct.

I think it's because in Sweden people speak a little different if you live in the Northern area or Southern area.

I would say "Hejdå"

[devalanteriel]

Both spelling variations are acceptable, but the one with the space is generally consider the prescribed option.