12859 ÷ 8 = 1607 R3
Alright, let's work through the division of 12859 by 8 step by step.

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 (8) of the dividend behind the 4 and repeat the process: 48 / 8

Step 3:
8 goes into 48 6 times with a remainder of 0.
Write down 6 as next digit of of the result. 
Result so far: 16
Subtract 48 from 48 to get 0.
Bring next digit (5) of the dividend behind the 0 and repeat the process: 5 / 8

Step 4:
8 goes into 5 0 times with a remainder of 5.
Write down 0 as next digit of of the result. 
Result so far: 160
Subtract 0 from 5 to get 5.
Bring next digit (9) of the dividend behind the 5 and repeat the process: 59 / 8

Step 5:
8 goes into 59 7 times with a remainder of 3.
Write down 7 as next digit of of the result. 
Result so far: 1607
Subtract 56 from 59 to get 3.

The final result is 1607 with a remainder of 3.