We can solve this together! We're beginning with 647134 and removing 3240 from it.

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

Step 2: We'll start by subtracting the digit 4 and the borrow 0 from 3 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 2 and the borrow 1 from 1 in column 3 and get -2.
We add -2 to 10 and get 8 as the next digit of the result.

Step 4: We'll start by subtracting the digit 3 and the borrow 1 from 7 in column 4 and get 3.
3 is the next digit of our result.

Step 5: We'll start by subtracting the digit 0 and the borrow 0 from 4 in column 5 and get 4.
4 is the next digit of our result.

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

So, 647134 - 3240 = 643894.