Alright, ready to do some subtraction? We're taking 742723709 and subtracting 320509290 from it.

Step 1: We'll start by subtracting the digit 0 and the borrow 0 from 9 in column 1 and get 9.
9 is the first digit of our result.

Step 2: We'll start by subtracting the digit 9 and the borrow 0 from 0 in column 2 and get -9.
We add -9 to 10 and get 1 as the next digit of the result.

Step 3: We'll start by subtracting the digit 2 and the borrow 1 from 7 in column 3 and get 4.
4 is the next digit of our result.

Step 4: We'll start by subtracting the digit 9 and the borrow 0 from 3 in column 4 and get -6.
We add -6 to 10 and get 4 as the next digit of the result.

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

Step 6: We'll start by subtracting the digit 5 and the borrow 0 from 7 in column 6 and get 2.
2 is the next digit of our result.

Step 7: We'll start by subtracting the digit 0 and the borrow 0 from 2 in column 7 and get 2.
2 is the next digit of our result.

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

Step 9: We'll start by subtracting the digit 3 and the borrow 0 from 7 in column 9 and get 4.
4 is the next digit of our result.

So, 742723709 - 320509290 = 422214419.