No problem, let's work through this together. We're starting with 742861 and are subtracting 99051 from it.

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

Step 2: We'll start by subtracting the digit 5 and the borrow 0 from 6 in column 2 and get 1.
1 is the next digit of our result.

Step 3: We'll start by subtracting the digit 0 and the borrow 0 from 8 in column 3 and get 8.
8 is the next digit of our result.

Step 4: We'll start by subtracting the digit 9 and the borrow 0 from 2 in column 4 and get -7.
We add -7 to 10 and get 3 as the next digit of the result.

Step 5: We'll start by subtracting the digit 9 and the borrow 1 from 4 in column 5 and get -6.
We add -6 to 10 and get 4 as the next digit of the result.

Step 6: We'll start by subtracting the digit 0 and the borrow 1 from 7 in column 6 and get 6.
6 is the next digit of our result.

So, 742861 - 99051 = 643810.