Okay, let's tackle this math problem. We're starting with 616900364 and subtracting 443149027.

Step 1: We'll start by subtracting the digit 7 and the borrow 0 from 4 in column 1 and get -3.
We add -3 to 10 and get 7 as the first digit of the result.

Step 2: We'll start by subtracting the digit 2 and the borrow 1 from 6 in column 2 and get 3.
3 is the next digit of our result.

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

Step 4: We'll start by subtracting the digit 9 and the borrow 0 from 0 in column 4 and get -9.
We add -9 to 10 and get 1 as the next digit of the result.

Step 5: We'll start by subtracting the digit 4 and the borrow 1 from 0 in column 5 and get -5.
We add -5 to 10 and get 5 as the next digit of the result.

Step 6: We'll start by subtracting the digit 1 and the borrow 1 from 9 in column 6 and get 7.
7 is the next digit of our result.

Step 7: We'll start by subtracting the digit 3 and the borrow 0 from 6 in column 7 and get 3.
3 is the next digit of our result.

Step 8: We'll start by subtracting the digit 4 and the borrow 0 from 1 in column 8 and get -3.
We add -3 to 10 and get 7 as the next digit of the result.

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

So, 616900364 - 443149027 = 173751337.