Respuesta :

For 27 it would be
1 2 3 4 + 1 2 + 3 + 4 1 2 + 3 4 1 2 + 3 + 4 1 + 2 3 4 1 2 3 4
For 28 it would be
1 2 3 4 1 2 + 3 4 1 2 3 4 + 1 2 3 4 1 2 3 + 4 +