400 ÷ 4 = 100 R0
No problem, we've got 400 and 4 for the division.

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

Step 2:
4 goes into 0 0 times with a remainder of 0.
Write down 0 as next digit of of the result. 
Result so far: 10
Subtract 0 from 0 to get 0.
Bring next digit (0) of the dividend behind the 0 and repeat the process: 0 / 4

Step 3:
4 goes into 0 0 times with a remainder of 0.
Write down 0 as next digit of of the result. 
Result so far: 100
Subtract 0 from 0 to get 0.

The final result is 100 with a remainder of 0.