6443 ÷ 4 = 1610 R3
No problem, we've got 6443 and 4 for the division.

Step 1:
4 goes into 6 1 times with a remainder of 2.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 4 from 6 to get 2.
Bring next digit (4) of the dividend behind the 2 and repeat the process: 24 / 4

Step 2:
4 goes into 24 6 times with a remainder of 0.
Write down 6 as next digit of of the result. 
Result so far: 16
Subtract 24 from 24 to get 0.
Bring next digit (4) of the dividend behind the 0 and repeat the process: 4 / 4

Step 3:
4 goes into 4 1 times with a remainder of 0.
Write down 1 as next digit of of the result. 
Result so far: 161
Subtract 4 from 4 to get 0.
Bring next digit (3) of the dividend behind the 0 and repeat the process: 3 / 4

Step 4:
4 goes into 3 0 times with a remainder of 3.
Write down 0 as next digit of of the result. 
Result so far: 1610
Subtract 0 from 3 to get 3.

The final result is 1610 with a remainder of 3.