SOLUTION: U={a,b,c,d,e,f} A=}a,b,d,e} B={b,c,f} C={c,d,e,} Find B-(AᑎC)

B-(AᑎC) 

Substitute the sets for the letters:

{b,c,f}-({a,b,d,e}ᑎ{c,d,e}}

Work inside the parentheses first, " ᑎ " means to take only 
the elements which are IN COMMON to both sets which " ᑎ " is in
between.  The only common elements are d and e.
So we have: 

{b,c,f}-{d,e}

To subtract one set from another set, remove any elements from
the first set which are in the second set, and ignore any elements
in the second set which are not in the first set.

There are no elements in the second set to remove from the first
set so we leave the first set as it is as the answer:

{b,c,f}, which is really just the set B.  It turned out that there
was nothing to remove from it.

Edwin