Let's get this math done. We have 91653 and 51503, and we're going to subtract the second number from the first.

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

Step 2: We'll start by subtracting the digit 0 and the borrow 0 from 5 in column 2 and get 5.
5 is the next digit of our result.

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

Step 4: We'll start by subtracting the digit 1 and the borrow 0 from 1 in column 4 and get 0.
0 is the next digit of our result.

Step 5: We'll start by subtracting the digit 5 and the borrow 0 from 9 in column 5 and get 4.
4 is the next digit of our result.

So, 91653 - 51503 = 40150.