Răspuns :
18 - ( 7 + 6 - 8 ) + 0 =
18 - ( 13 - 8 ) + 0 =
18 - 5 + 0 =
13 + 0 = 13
4 + ( 12 - 5 + 3 ) - 8 =
4 + ( 7 + 3 ) - 8 =
4 + 10 - 8 =
14 - 8 = 6
20 - ( 17 - 8 - 4 ) + 5 =
20 - 5 + 5 =
15 + 5 = 20
18 - ( 7 + 6 - 8 ) + 0 =
18 - ( 13 - 8 ) + 0 =
18 - 5 + 0 =
13 + 0 = 13
4 + ( 12 - 5 + 3 ) - 8 =
4 + ( 7 + 3 ) - 8 =
4 + 10 - 8 =
14 - 8 = 6
20 - ( 17 - 8 - 4 ) + 5 =
20 - 5 + 5 =
15 + 5 = 20