Let's dive into this subtraction. We'll start with 879426 and subtract 19773 from it.

Step 1: We'll start by subtracting the digit 3 and the borrow 0 from 6 in column 1 and get 3.
3 is the first digit of our result.

Step 2: We'll start by subtracting the digit 7 and the borrow 0 from 2 in column 2 and get -5.
We add -5 to 10 and get 5 as the next digit of the result.

Step 3: We'll start by subtracting the digit 7 and the borrow 1 from 4 in column 3 and get -4.
We add -4 to 10 and get 6 as the next digit of the result.

Step 4: We'll start by subtracting the digit 9 and the borrow 1 from 9 in column 4 and get -1.
We add -1 to 10 and get 9 as the next digit of the result.

Step 5: We'll start by subtracting the digit 1 and the borrow 1 from 7 in column 5 and get 5.
5 is the next digit of our result.

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

So, 879426 - 19773 = 859653.