No problem, let's work through this together. We're starting with 689799 and are subtracting 44709 from it.

Step 1: We'll start by subtracting the digit 9 and the borrow 0 from 9 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 9 in column 2 and get 9.
9 is the next digit of our result.

Step 3: We'll start by subtracting the digit 7 and the borrow 0 from 7 in column 3 and get 0.
0 is the next digit of our result.

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

Step 5: We'll start by subtracting the digit 4 and the borrow 0 from 8 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 6 in column 6 and get 6.
6 is the next digit of our result.

So, 689799 - 44709 = 645090.