"One newspaper, several newspapers"
Translation:En tidning, flera tidningar
Have a look at the second and third topics here: https://forum.duolingo.com/comment/26420394/Answers-to-some-common-questions-on-grammar-that-beginners-have
I think you missed a section. Here, I'll copy-paste:
How do I know the gender of a word just by looking at it?
I am sorry to say that the gender of a word will most often need to be learned by heart. This post by Zzzzz... has a great list of tendencies, however: https://www.duolingo.com/comment/6329293