Alright, ready to do some subtraction? We're taking 65603 and subtracting 35458 from it.

Step 1: We'll start by subtracting the digit 8 and the borrow 0 from 3 in column 1 and get -5.
We add -5 to 10 and get 5 as the first digit of the result.

Step 2: We'll start by subtracting the digit 5 and the borrow 1 from 0 in column 2 and get -6.
We add -6 to 10 and get 4 as the next digit of the result.

Step 3: We'll start by subtracting the digit 4 and the borrow 1 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 5 and the borrow 0 from 5 in column 4 and get 0.
0 is the next digit of our result.

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

So, 65603 - 35458 = 30145.