Alright, let's solve this problem step by step. We have 668462 and 72152, and we're subtracting the second number from the first.

Step 1: We'll start by subtracting the digit 2 and the borrow 0 from 2 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 1 and the borrow 0 from 4 in column 3 and get 3.
3 is the next digit of our result.

Step 4: We'll start by subtracting the digit 2 and the borrow 0 from 8 in column 4 and get 6.
6 is the next digit of our result.

Step 5: We'll start by subtracting the digit 7 and the borrow 0 from 6 in column 5 and get -1.
We add -1 to 10 and get 9 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, 668462 - 72152 = 596310.