Why is it "mit den Jungs" rather than "mit dem Jungs"
Was recently going through the dative case module and it asked me to translate the sentence:
"The chicken plays with the boys"
So I typed down my answer as: Der Hähnchen spielt mit dem Jungs?
Duolingo tells me that this is however incorrect as it's in the acc. case. Now I understand the whole concept of why it should be acc. but I was always told that Mit is a dative preposition. If that is the case then shouldn't it be dem (Jungs is masc, mit is dative)?
I know i am probably wrong here, but this is why I'm asking.