12990 ÷ 8 = 1623 R6
Let's divide 12990 by 8.

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 (9) of the dividend behind the 4 and repeat the process: 49 / 8

Step 3:
8 goes into 49 6 times with a remainder of 1.
Write down 6 as next digit of of the result. 
Result so far: 16
Subtract 48 from 49 to get 1.
Bring next digit (9) of the dividend behind the 1 and repeat the process: 19 / 8

Step 4:
8 goes into 19 2 times with a remainder of 3.
Write down 2 as next digit of of the result. 
Result so far: 162
Subtract 16 from 19 to get 3.
Bring next digit (0) of the dividend behind the 3 and repeat the process: 30 / 8

Step 5:
8 goes into 30 3 times with a remainder of 6.
Write down 3 as next digit of of the result. 
Result so far: 1623
Subtract 24 from 30 to get 6.

The final result is 1623 with a remainder of 6.