We divide 39204 by 21
We're looking to find how many times 21 goes into 39204.

Let's proceed to step 1:
When dividing 3 by 21, we get 0 with a remainder of 3.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 3, we end up with 3.
Include the next digit (9) from the dividend after 3, then repeat: 39 / 21

Let's proceed to step 2:
When dividing 39 by 21, we get 1 with a remainder of 18.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
The remainder is 18 after subtracting 21 from 39.
Bring next digit (2) of the dividend behind the 18 and repeat the process: 182 / 21

Advancing to step 3:
21 can be fit into 182 8 times, resulting in a remainder of 14.
The next digit of our result is 8. 
Result so far: 18.0
Deduct 168 from 182 and we're left with 14.
Take the next digit (0) from the dividend and append it to 14, then repeat: 140 / 21

Let's proceed to step 4:
21 can be fit into 140 6 times, resulting in a remainder of 14.
The next digit of our result is 6. 
Result so far: 186.0
If we subtract 126 from 140, we get 14.
Bring next digit (4) of the dividend behind the 14 and repeat the process: 144 / 21

On to step 5:
When dividing 144 by 21, we get 6 with a remainder of 18.
Put 6 as the next digit of the answer. 
Result so far: 1866.0
If we take 126 away from 144, we end up with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Step 6:
The number 21 fits into 180 8 times, leaving a remainder of 12.
Put 8 as the next digit of the answer. 
Result so far: 1866.8
Subtract 168 from 180 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Moving on to step 7:
If we divide 120 by 21, we get 5 and a remainder of 15.
Use 5 as the next digit of our solution. 
Result so far: 1866.85
Subtract 105 from 120 to get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Step 8:
If we divide 150 by 21, we get 7 and a remainder of 3.
Put 7 as the next digit of the answer. 
Result so far: 1866.857
The remainder is 3 after subtracting 147 from 150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Advancing to step 9:
21 can be fit into 30 1 times, resulting in a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 1866.8571
Subtracting 21 from 30 leaves us with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Moving on to step 10:
The number 21 fits into 90 4 times, leaving a remainder of 6.
The next digit of our result is 4. 
Result so far: 1866.85714
If we subtract 84 from 90, we get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

On to step 11:
If we divide 60 by 21, we get 2 and a remainder of 18.
Write down 2 as next digit of the result. 
Result so far: 1866.857142
Deduct 42 from 60 and we're left with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Going ahead to step 12:
When dividing 180 by 21, we get 8 with a remainder of 12.
Use 8 as the next digit of our solution. 
Result so far: 1866.8571428
Subtract 168 from 180 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 13:
21 goes into 120 5 times with a remainder of 15.
The number 5 becomes the next digit in our result. 
Result so far: 1866.85714285
If we take 105 away from 120, we end up with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

The quotient of the division is 1866.85714285, and the remainder is 1.5e-08.