12420 ÷ 8 = 1552 R4
Alright, let's work through the division of 12420 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 (4) of the dividend behind the 4 and repeat the process: 44 / 8

Step 3:
8 goes into 44 5 times with a remainder of 4.
Write down 5 as next digit of of the result. 
Result so far: 15
Subtract 40 from 44 to get 4.
Bring next digit (2) of the dividend behind the 4 and repeat the process: 42 / 8

Step 4:
8 goes into 42 5 times with a remainder of 2.
Write down 5 as next digit of of the result. 
Result so far: 155
Subtract 40 from 42 to get 2.
Bring next digit (0) of the dividend behind the 2 and repeat the process: 20 / 8

Step 5:
8 goes into 20 2 times with a remainder of 4.
Write down 2 as next digit of of the result. 
Result so far: 1552
Subtract 16 from 20 to get 4.

The final result is 1552 with a remainder of 4.