81640 ÷ 8 = 10205 R0
We're going to perform division on 81640 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 (6) of the dividend behind the 1 and repeat the process: 16 / 8

Step 3:
8 goes into 16 2 times with a remainder of 0.
Write down 2 as next digit of of the result. 
Result so far: 102
Subtract 16 from 16 to get 0.
Bring next digit (4) of the dividend behind the 0 and repeat the process: 4 / 8

Step 4:
8 goes into 4 0 times with a remainder of 4.
Write down 0 as next digit of of the result. 
Result so far: 1020
Subtract 0 from 4 to get 4.
Bring next digit (0) of the dividend behind the 4 and repeat the process: 40 / 8

Step 5:
8 goes into 40 5 times with a remainder of 0.
Write down 5 as next digit of of the result. 
Result so far: 10205
Subtract 40 from 40 to get 0.

The final result is 10205 with a remainder of 0.