Let's dive into this subtraction. We'll start with 649074020 and subtract 243225025 from it.

Step 1: We'll start by subtracting the digit 5 and the borrow 0 from 0 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 2 and the borrow 1 from 2 in column 2 and get -1.
We add -1 to 10 and get 9 as the next digit of the result.

Step 3: We'll start by subtracting the digit 0 and the borrow 1 from 0 in column 3 and get -1.
We add -1 to 10 and get 9 as the next digit of the result.

Step 4: We'll start by subtracting the digit 5 and the borrow 1 from 4 in column 4 and get -2.
We add -2 to 10 and get 8 as the next digit of the result.

Step 5: We'll start by subtracting the digit 2 and the borrow 1 from 7 in column 5 and get 4.
4 is the next digit of our result.

Step 6: We'll start by subtracting the digit 2 and the borrow 0 from 0 in column 6 and get -2.
We add -2 to 10 and get 8 as the next digit of the result.

Step 7: We'll start by subtracting the digit 3 and the borrow 1 from 9 in column 7 and get 5.
5 is the next digit of our result.

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

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

So, 649074020 - 243225025 = 405848995.