Let's dive into this subtraction. We'll start with 959953 and subtract 21907 from it.

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 0 and the borrow 1 from 5 in column 2 and get 4.
4 is the next digit of our result.

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

Step 4: We'll start by subtracting the digit 1 and the borrow 0 from 9 in column 4 and get 8.
8 is the next digit of our result.

Step 5: We'll start by subtracting the digit 2 and the borrow 0 from 5 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 9 in column 6 and get 9.
9 is the next digit of our result.

So, 959953 - 21907 = 938046.