# Thread: Order of Operation for Set Notation

1. ## Order of Operation for Set Notation

Hello all,

Let:
U = {1,2,3,...,10}
A = {1,4,7,10}
B= {1,2,3,4,5}
C = {2,4,6,8}
u = union symbol
n = intersection symbol

(not A) n (not B) u (C)

After evaluating the not A and not B should the (not B) u (C) be evaluated first or should (not A) n (not B) be evaluated first?

2. Originally Posted by sedemihcra
Hello all,

Let:
U = {1,2,3,...,10}
A = {1,4,7,10}
B= {1,2,3,4,5}
C = {2,4,6,8}
u = union symbol
n = intersection symbol

(not A) n (not B) u (C)

After evaluating the not A and not B should the (not B) u (C) be evaluated first or should (not A) n (not B) be evaluated first?
This doesn't make sense. Are you missing parentheses?

3. For that problem there are no parentheses. Also the not is over the A and the B, but not the C. Would that indicate that I should evaluate the (not A) n (not B) then the u C?

The above statement is wrong. I misused De Morgan's laws for sets. I forgot to switch the intersection symbol to a union symbol. The problem should read:
(not A) u (not B) u (C)