Okay, let's tackle this math problem. We're starting with 649218 and subtracting 60879.

Step 1: We'll start by subtracting the digit 9 and the borrow 0 from 8 in column 1 and get -1.
We add -1 to 10 and get 9 as the first digit of the result.

Step 2: We'll start by subtracting the digit 7 and the borrow 1 from 1 in column 2 and get -7.
We add -7 to 10 and get 3 as the next digit of the result.

Step 3: We'll start by subtracting the digit 8 and the borrow 1 from 2 in column 3 and get -7.
We add -7 to 10 and get 3 as the next digit of the result.

Step 4: We'll start by subtracting the digit 0 and the borrow 1 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 6 and the borrow 0 from 4 in column 5 and get -2.
We add -2 to 10 and get 8 as the next digit of the result.

Step 6: We'll start by subtracting the digit 0 and the borrow 1 from 6 in column 6 and get 5.
5 is the next digit of our result.

So, 649218 - 60879 = 588339.