4121 ÷ 8 = 515 R1
Let's divide 4121 by 8.

Step 1:
8 goes into 4 0 times with a remainder of 4.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 4 to get 4.
Bring next digit (1) of the dividend behind the 4 and repeat the process: 41 / 8

Step 2:
8 goes into 41 5 times with a remainder of 1.
Write down 5 as next digit of of the result. 
Result so far: 5
Subtract 40 from 41 to get 1.
Bring next digit (2) of the dividend behind the 1 and repeat the process: 12 / 8

Step 3:
8 goes into 12 1 times with a remainder of 4.
Write down 1 as next digit of of the result. 
Result so far: 51
Subtract 8 from 12 to get 4.
Bring next digit (1) of the dividend behind the 4 and repeat the process: 41 / 8

Step 4:
8 goes into 41 5 times with a remainder of 1.
Write down 5 as next digit of of the result. 
Result so far: 515
Subtract 40 from 41 to get 1.

The final result is 515 with a remainder of 1.