389780 divided by 21 
Let's see how many times 21 fits into 389780.

Going ahead 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.
Bring next digit (8) of the dividend behind the 3 and repeat the process: 38 / 21

On to step 2:
When dividing 38 by 21, we get 1 with a remainder of 17.
Put 1 as the next digit of the answer. 
Result so far: 1.0
If we take 21 away from 38, we end up with 17.
Bring next digit (9) of the dividend behind the 17 and repeat the process: 179 / 21

Going ahead to step 3:
When dividing 179 by 21, we get 8 with a remainder of 11.
Record the quotient 8 as the next digit in the result. 
Result so far: 18.0
If we take 168 away from 179, we end up with 11.
Include the next digit (7) from the dividend after 11, then repeat: 117 / 21

Going ahead to step 4:
117 divided by 21 is 5 with a remainder of 12.
The next digit of our result is 5. 
Result so far: 185.0
The remainder is 12 after subtracting 105 from 117.
Grab the next digit (8) from the dividend, add it to 12, then carry on: 128 / 21

Moving on to step 5:
When dividing 128 by 21, we get 6 with a remainder of 2.
Write down 6 as next digit of the result. 
Result so far: 1856.0
If we take 126 away from 128, we end up with 2.
Take the next digit (0) from the dividend and append it to 2, then repeat: 20 / 21

Step 6:
20 divided by 21 is 0 with a remainder of 20.
Record the quotient 0 as the next digit in the result. 
Result so far: 18560.0
If we subtract 0 from 20, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Step 7:
21 goes into 200 9 times with a remainder of 11.
The number 9 becomes the next digit in our result. 
Result so far: 18560.9
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.

On to step 8:
When dividing 110 by 21, we get 5 with a remainder of 5.
The next digit of our result is 5. 
Result so far: 18560.95
The remainder is 5 after subtracting 105 from 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

On to step 9:
21 can be fit into 50 2 times, resulting in a remainder of 8.
The next digit of our result is 2. 
Result so far: 18560.952
Subtracting 42 from 50 leaves us 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.

Advancing to step 10:
21 can be fit into 80 3 times, resulting in a remainder of 17.
The number 3 becomes the next digit in our result. 
Result so far: 18560.9523
The remainder is 17 after subtracting 63 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

On to step 11:
21 can be fit into 170 8 times, resulting in a remainder of 2.
Use 8 as the next digit of our solution. 
Result so far: 18560.95238
Subtract 168 from 170 to 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.

On to step 12:
If we divide 20 by 21, we get 0 and a remainder of 20.
Record the quotient 0 as the next digit in the result. 
Result so far: 18560.95238
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.

On to step 13:
The number 21 fits into 200 9 times, leaving a remainder of 11.
Use 9 as the next digit of our solution. 
Result so far: 18560.9523809
Subtracting 189 from 200 leaves us 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.

On to step 14:
When dividing 110 by 21, we get 5 with a remainder of 5.
Write down 5 as next digit of the result. 
Result so far: 18560.95238095
If we take 105 away from 110, we end up 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.

The final outcome is 18560.95238095, with a leftover of 5e-09.