Okay, let's tackle this math problem. We're starting with 70902 and subtracting 59623.

Step 1: We'll start by subtracting the digit 3 and the borrow 0 from 2 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 2 and the borrow 1 from 0 in column 2 and get -3.
We add -3 to 10 and get 7 as the next digit of the result.

Step 3: We'll start by subtracting the digit 6 and the borrow 1 from 9 in column 3 and get 2.
2 is the next digit of our result.

Step 4: We'll start by subtracting the digit 9 and the borrow 0 from 0 in column 4 and get -9.
We add -9 to 10 and get 1 as the next digit of the result.

Step 5: We'll start by subtracting the digit 5 and the borrow 1 from 7 in column 5 and get 1.
1 is the next digit of our result.

So, 70902 - 59623 = 11279.