It is 19
+6
13 and 5/6
Seven is added each time. 6 + 7 = 13 13 + 7 = 20 And so on...
22
13
29
1 + 2 + 4 + 6 = 13
16
55
13-12=1. Added to the original 1 = 2 10-4=6 6/2 (from the first line) = 3 !
No, no two of the numbers : 6 13 2 12 7 14 can be added up to produce 17.
+6