383990 ÷ 21 
We want to divide 383990 by 21.

Moving on to step 1:
3 divided by 21 is 0 with a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 3, we end up with 3.
Take the next digit (8) from the dividend and append it to 3, then repeat: 38 / 21

Advancing to step 2:
When dividing 38 by 21, we get 1 with a remainder of 17.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we subtract 21 from 38, we get 17.
Bring next digit (3) of the dividend behind the 17 and repeat the process: 173 / 21

Let's proceed to step 3:
When dividing 173 by 21, we get 8 with a remainder of 5.
The next digit of our result is 8. 
Result so far: 18.0
Subtract 168 from 173 to get 5.
Bring next digit (9) of the dividend behind the 5 and repeat the process: 59 / 21

Advancing to step 4:
The number 21 fits into 59 2 times, leaving a remainder of 17.
Write down 2 as next digit of the result. 
Result so far: 182.0
If we take 42 away from 59, we end up with 17.
Include the next digit (9) from the dividend after 17, then repeat: 179 / 21

Let's proceed to step 5:
The number 21 fits into 179 8 times, leaving a remainder of 11.
Write down 8 as next digit of the result. 
Result so far: 1828.0
If we take 168 away from 179, we end up with 11.
Append the next digit (0) from the dividend to 11 and continue with: 110 / 21

On to step 6:
21 can be fit into 110 5 times, resulting in a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 18285.0
Deduct 105 from 110 and we're left with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Going ahead to step 7:
50 divided by 21 is 2 with a remainder of 8.
The next digit of our result is 2. 
Result so far: 18285.2
Subtract 42 from 50 to get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Let's proceed to step 8:
21 goes into 80 3 times with a remainder of 17.
The number 3 becomes the next digit in our result. 
Result so far: 18285.23
If we subtract 63 from 80, we get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Advancing to step 9:
When dividing 170 by 21, we get 8 with a remainder of 2.
Record the quotient 8 as the next digit in the result. 
Result so far: 18285.238
If we subtract 168 from 170, we get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Step 10:
21 goes into 20 0 times with a remainder of 20.
The next digit of our result is 0. 
Result so far: 18285.238
If we take 0 away from 20, we end up with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Let's proceed to step 11:
21 can be fit into 200 9 times, resulting in a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 18285.23809
If we take 189 away from 200, we end up with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 12:
When dividing 110 by 21, we get 5 with a remainder of 5.
Use 5 as the next digit of our solution. 
Result so far: 18285.238095
Deduct 105 from 110 and we're left with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Let's proceed to step 13:
The number 21 fits into 50 2 times, leaving a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 18285.2380952
If we take 42 away from 50, we end up with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Let's proceed to step 14:
If we divide 80 by 21, we get 3 and a remainder of 17.
Record the quotient 3 as the next digit in the result. 
Result so far: 18285.23809523
If we take 63 away from 80, we end up with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Our division results in 18285.23809523 with a remaining 1.7e-08.