39021 ÷ 4 = 9755 R1
We're going to perform division on 39021 with 4 as the divisor.

Step 1:
4 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 / 4

Step 2:
4 goes into 39 9 times with a remainder of 3.
Write down 9 as next digit of of the result. 
Result so far: 9
Subtract 36 from 39 to get 3.
Bring next digit (0) of the dividend behind the 3 and repeat the process: 30 / 4

Step 3:
4 goes into 30 7 times with a remainder of 2.
Write down 7 as next digit of of the result. 
Result so far: 97
Subtract 28 from 30 to get 2.
Bring next digit (2) of the dividend behind the 2 and repeat the process: 22 / 4

Step 4:
4 goes into 22 5 times with a remainder of 2.
Write down 5 as next digit of of the result. 
Result so far: 975
Subtract 20 from 22 to get 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 4

Step 5:
4 goes into 21 5 times with a remainder of 1.
Write down 5 as next digit of of the result. 
Result so far: 9755
Subtract 20 from 21 to get 1.

The final result is 9755 with a remainder of 1.