Got it! So, we have 946664 and 4019, and we'll subtract the latter from the former.

Step 1: We'll start by subtracting the digit 9 and the borrow 0 from 4 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 1 and the borrow 1 from 6 in column 2 and get 4.
4 is the next digit of our result.

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

Step 4: We'll start by subtracting the digit 4 and the borrow 0 from 6 in column 4 and get 2.
2 is the next digit of our result.

Step 5: We'll start by subtracting the digit 0 and the borrow 0 from 4 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, 946664 - 4019 = 942645.