A' U B U C' {a,o}' U {a,e,i} U {e,i,o,u}' We get rid of the primes ' (complement sets) by replacing the set with all the elements in the universal set which are NOT in that set: {e,i,u} U (a,e,i} U {a} Now U means we put all those elements together in one set: {a,e,i,u} Edwin