Sure thing! We've got 998989 and 53508, and we're going to subtract the second number from the first.

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 0 and the borrow 0 from 8 in column 2 and get 8.
8 is the next digit of our result.

Step 3: We'll start by subtracting the digit 5 and the borrow 0 from 9 in column 3 and get 4.
4 is the next digit of our result.

Step 4: We'll start by subtracting the digit 3 and the borrow 0 from 8 in column 4 and get 5.
5 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.

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, 998989 - 53508 = 945481.