"Dad likes to dance with mom."
Translation:Тато любить танцювати з мамою.
Why can't this end with just "мама"? It said it should be "мамою"
Мама is in Nominative (when plays a role of a subject which it does not in this sentence), and мамою is in Instrumentalis (for using it and doing something with it)
With mom = з мамою, with (a) carrot = з морквою, with a car = з машиною...
I think the general rule is "тато" - "dad", "батько" - "father" in this course. They are interchangeable in the sense that they refer to the same "person", but as words they are slightly different... So I guess the differentiation which is very subtle is introduced anyway to see that you learned both words.