9021 ÷ 9 = 1002 R3
We're going to perform division on 9021 with 9 as the divisor.

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

Step 2:
9 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 (2) of the dividend behind the 0 and repeat the process: 2 / 9

Step 3:
9 goes into 2 0 times with a remainder of 2.
Write down 0 as next digit of of the result. 
Result so far: 100
Subtract 0 from 2 to get 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 9

Step 4:
9 goes into 21 2 times with a remainder of 3.
Write down 2 as next digit of of the result. 
Result so far: 1002
Subtract 18 from 21 to get 3.

The final result is 1002 with a remainder of 3.