3931 ÷ 9 = 436 R7
No problem, we've got 3931 and 9 for the division.

Step 1:
9 goes into 3 0 times with a remainder of 3.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 3 to get 3.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 9

Step 2:
9 goes into 39 4 times with a remainder of 3.
Write down 4 as next digit of of the result. 
Result so far: 4
Subtract 36 from 39 to get 3.
Bring next digit (3) of the dividend behind the 3 and repeat the process: 33 / 9

Step 3:
9 goes into 33 3 times with a remainder of 6.
Write down 3 as next digit of of the result. 
Result so far: 43
Subtract 27 from 33 to get 6.
Bring next digit (1) of the dividend behind the 6 and repeat the process: 61 / 9

Step 4:
9 goes into 61 6 times with a remainder of 7.
Write down 6 as next digit of of the result. 
Result so far: 436
Subtract 54 from 61 to get 7.

The final result is 436 with a remainder of 7.