SET OPERATION
U={p,q,r,s,t,u,v,w}
A=r,s,t,u,w
B=p,q,r,s,t
C=q,s,u,w

find each set
C-B
(A-C)-C-B
(C-B)-A
A-C
(A-C)-(C-B)

Question

SET OPERATION 
U={p,q,r,s,t,u,v,w}
A=r,s,t,u,w
B=p,q,r,s,t
C=q,s,u,w

find each set
C-B
(A-C)-C-B
(C-B)-A
A-C
(A-C)-(C-B)

shadowfiend · Answer

So, generally speaking, you have to ask yourself, `what does set difference mean'. Subtracting a set X from a set Y, Y - Z, means producing a new set that includes all of the elements in Y that are not in Z.

As an example, I'll do the first one (C - B); let me know if that helps:

C - B

C consists of q s u w
B consists of p q r s t

B has q and s which are both in C.

So, C - B is q s u w without q and s, so it is u and w:

C - B = {u, w}