Question on Beginners Spanish Chapter 2

I have a question concerning Exercise 1, Question 6. It is asking for the right verb conjugation. The sentence is "Casuela y yo nadar los fines de semana.". I put nadan for the conjugation, but the answer in the book claims nadamos. Why is this the we form? I could see if this sentence had been part of a paragraph where I could then use we instead of Casuela and I, but that is not the case her. Also, why is "los fines" used instead of "el fin". If semana had been plural, "semenas", I could see "los fines" if in fact this means weekends. Thank you. Henk

Hola Henk. You need to use "nadamos" because you're talking about "Casuela and I." Since you're one of the people doing the swimming, you'd say "we," not "they." It's the same in English--If you say "he and I go swimming," you'd say "WE go swimming," not "they go swimming." As for "los fines," the plural of "el fin de semana" is "los fines de semana." Again, it's somewhat like English. In English, the plural of "weekend" is "weekends," not weeksends. I hope that helps.

Thank you! And yes, it is very helpful. Henk