Answer
196
Work Step by Step
First column: 8 - 2 = 6
The 6 is written in the first column.
Second column: 6 - 7 is turned into 16 - 7 as 6 < 7 - 16 - 7 = 9
The 9 is written in the second column and the extra 1 digit added in the tens position to the 6 is carried to the next column.
Third column: 9 - 7 - additional carried 1 from the previous column = 1
The 1 is written in the last column.
The digits we are left with are 1, 9 and 6, so therefore the solution to the question is 196.