If there are 17 students in set​ A, Addi’s kindergarten​ class, and there are 84 students in set​ B, the freshman high school​ class, what is n (A∪B)​?

Question

Trying to figure out the answer I'm stuck on this question right here. Would appreciate if someone could help me out,

Answer 1

n(A) = 17

n(B) = 84

 

n(AUB) = n(A) + n(B) - n(A∩B)

 

n(A∩B) = the number of students who are both kindergartners and freshman in high school.  Not many kindergartners are also freshman in HS, so I'm guessing that number is 0.

 

n(AUB) = n(A) + n(B) - n(A∩B)

n(AUB) = 17 + 84 - 0 = ____