 First, we subtract the rightmost column. 1 minus 0 equals 1.

10101
 01110
1

 In order to subtract the second column, we need to borrow a
1. So we cross out the 1 in the third column, and represent it
as two 1s in the second column.

1
01
10101
 01110
1

 We can now subtract 1 from the group of two borrowed 1s. This
leaves us with 1, so we write it below the second column.

1
01
10101
 01110
11

 Now we subtract the next column. Since we borrowed from this
column, the subtraction is 0 minus 1 and we must borrow again.
However, our next column has no 1 for us to borrow. So, we must
first borrow from the last column.

1 1
0101
10101
 01110
11

 Then borrow a 1 from the fourth column into our current column.

1
111
0101
10101
 01110
11

 We can now perform the subtraction for the current column.
We take 1 away from our group of two blue 1s. This leaves us with
a single 1 which we write below the column.

1
111
0101
10101
 01110
111

 In the fourth column, we subtract 1 from 1 for a result of 0.

1
111
0101
10101
 01110
0111

 Our last column contains contains all zeros, so we write 0 below
it. This gives us our answer of 00111_{2}.

1
111
0101
10101
 01110
00111
