Okay, let's tackle this math problem. We're starting with 590503 and subtracting 55387.

Step 1: We'll start by subtracting the digit 7 and the borrow 0 from 3 in column 1 and get -4.
We add -4 to 10 and get 6 as the first digit of the result.

Step 2: We'll start by subtracting the digit 8 and the borrow 1 from 0 in column 2 and get -9.
We add -9 to 10 and get 1 as the next digit of the result.

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

Step 4: We'll start by subtracting the digit 5 and the borrow 0 from 0 in column 4 and get -5.
We add -5 to 10 and get 5 as the next digit of the result.

Step 5: We'll start by subtracting the digit 5 and the borrow 1 from 9 in column 5 and get 3.
3 is the next digit of our result.

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

So, 590503 - 55387 = 535116.