12102 ÷ 8 = 1512 R6
We're going to perform division on 12102 with 8 as the divisor.

Step 1:
8 goes into 1 0 times with a remainder of 1.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 1 to get 1.
Bring next digit (2) of the dividend behind the 1 and repeat the process: 12 / 8

Step 2:
8 goes into 12 1 times with a remainder of 4.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 8 from 12 to get 4.
Bring next digit (1) of the dividend behind the 4 and repeat the process: 41 / 8

Step 3:
8 goes into 41 5 times with a remainder of 1.
Write down 5 as next digit of of the result. 
Result so far: 15
Subtract 40 from 41 to get 1.
Bring next digit (0) of the dividend behind the 1 and repeat the process: 10 / 8

Step 4:
8 goes into 10 1 times with a remainder of 2.
Write down 1 as next digit of of the result. 
Result so far: 151
Subtract 8 from 10 to get 2.
Bring next digit (2) of the dividend behind the 2 and repeat the process: 22 / 8

Step 5:
8 goes into 22 2 times with a remainder of 6.
Write down 2 as next digit of of the result. 
Result so far: 1512
Subtract 16 from 22 to get 6.

The final result is 1512 with a remainder of 6.