Do the following problems without a calculator:

Problem : 86 + 92 - 86 = ?

92

Problem : 68/12×(8 + 4) = ?

68

Problem : 17 - (19×6)/6 + (7 + 19 - 7) = ?

17

Find the number that fits into the question mark.

Problem : 82 - 19 + ?  = 82

19

Problem : (73/?)×14 = 73

14

Problem : 12/7×(3 + ?) = 12

4