351 ÷ 9 = 39 R0
Let's divide 351 by 9.

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 (5) of the dividend behind the 3 and repeat the process: 35 / 9

Step 2:
9 goes into 35 3 times with a remainder of 8.
Write down 3 as next digit of of the result. 
Result so far: 3
Subtract 27 from 35 to get 8.
Bring next digit (1) of the dividend behind the 8 and repeat the process: 81 / 9

Step 3:
9 goes into 81 9 times with a remainder of 0.
Write down 9 as next digit of of the result. 
Result so far: 39
Subtract 81 from 81 to get 0.

The final result is 39 with a remainder of 0.