Respuesta :
U={0,1,2,3, 4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19}
N={1,2,3,6,9,18}
N={1,2,3,6,9,18}
This is from the answer key to this question;
N= {4, 5, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 19.}