-21
1 + 19 + 0 + 1 = 21
It is 35.
The answer is 21
7/21 + 3/21 = 1021
14/21 + 1/7 = 17/21
6/7 = 18/21 + 1/21 = 19/21
29
26 - 21 = 5 or 24 - 23 = 1
5/7 + 1/3 = 15/21 + 7/21 = 22/21 = 1 1/21
2/3 + 1/7 + 4/6 = 14/21 + 3/21 + 14/21 = 31/21 = 1 10/21
20 + 1 = 21