Okay, let's tackle this math problem. We're starting with 913699 and subtracting 13168.

Step 1: We'll start by subtracting the digit 8 and the borrow 0 from 9 in column 1 and get 1.
1 is the first digit of our result.

Step 2: We'll start by subtracting the digit 6 and the borrow 0 from 9 in column 2 and get 3.
3 is the next digit of our result.

Step 3: We'll start by subtracting the digit 1 and the borrow 0 from 6 in column 3 and get 5.
5 is the next digit of our result.

Step 4: We'll start by subtracting the digit 3 and the borrow 0 from 3 in column 4 and get 0.
0 is the next digit of our result.

Step 5: We'll start by subtracting the digit 1 and the borrow 0 from 1 in column 5 and get 0.
0 is the next digit of our result.

Step 6: We'll start by subtracting the digit 0 and the borrow 0 from 9 in column 6 and get 9.
9 is the next digit of our result.

So, 913699 - 13168 = 900531.