81039 ÷ 8 = 10129 R7
We're going to perform division on 81039 with 8 as the divisor.

Step 1:
8 goes into 8 1 times with a remainder of 0.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 8 from 8 to get 0.
Bring next digit (1) of the dividend behind the 0 and repeat the process: 1 / 8

Step 2:
8 goes into 1 0 times with a remainder of 1.
Write down 0 as next digit of of the result. 
Result so far: 10
Subtract 0 from 1 to get 1.
Bring next digit (0) of the dividend behind the 1 and repeat the process: 10 / 8

Step 3:
8 goes into 10 1 times with a remainder of 2.
Write down 1 as next digit of of the result. 
Result so far: 101
Subtract 8 from 10 to get 2.
Bring next digit (3) of the dividend behind the 2 and repeat the process: 23 / 8

Step 4:
8 goes into 23 2 times with a remainder of 7.
Write down 2 as next digit of of the result. 
Result so far: 1012
Subtract 16 from 23 to get 7.
Bring next digit (9) of the dividend behind the 7 and repeat the process: 79 / 8

Step 5:
8 goes into 79 9 times with a remainder of 7.
Write down 9 as next digit of of the result. 
Result so far: 10129
Subtract 72 from 79 to get 7.

The final result is 10129 with a remainder of 7.