Let's divide 615021 by 21
We want to divide 615021 by 21.

Step 1:
21 can be fit into 6 0 times, resulting in a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Bring next digit (1) of the dividend behind the 6 and repeat the process: 61 / 21

Going ahead to step 2:
61 divided by 21 is 2 with a remainder of 19.
Write down 2 as next digit of the result. 
Result so far: 2.0
Subtract 42 from 61 to get 19.
Append the next digit (5) from the dividend to 19 and continue with: 195 / 21

Moving on to step 3:
21 can be fit into 195 9 times, resulting in a remainder of 6.
Record the quotient 9 as the next digit in the result. 
Result so far: 29.0
The remainder is 6 after subtracting 189 from 195.
Take the next digit (0) from the dividend and append it to 6, then repeat: 60 / 21

Advancing to step 4:
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: 292.0
Subtract 42 from 60 to get 18.
Grab the next digit (2) from the dividend, add it to 18, then carry on: 182 / 21

Step 5:
21 goes into 182 8 times with a remainder of 14.
Put 8 as the next digit of the answer. 
Result so far: 2928.0
Subtracting 168 from 182 leaves us with 14.
Include the next digit (1) from the dividend after 14, then repeat: 141 / 21

Advancing to step 6:
21 goes into 141 6 times with a remainder of 15.
The number 6 becomes the next digit in our result. 
Result so far: 29286.0
Subtract 126 from 141 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.

Going ahead to step 7:
If we divide 150 by 21, we get 7 and a remainder of 3.
The next digit of our result is 7. 
Result so far: 29286.7
If we take 147 away from 150, we end up with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Step 8:
21 goes into 30 1 times with a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 29286.71
If we take 21 away from 30, we end up 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.

Let's proceed to step 9:
The number 21 fits into 90 4 times, leaving a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 29286.714
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.

Let's proceed to step 10:
The number 21 fits into 60 2 times, leaving a remainder of 18.
Record the quotient 2 as the next digit in the result. 
Result so far: 29286.7142
If we subtract 42 from 60, we get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Moving on to step 11:
If we divide 180 by 21, we get 8 and a remainder of 12.
Write down 8 as next digit of the result. 
Result so far: 29286.71428
If we take 168 away from 180, we end up with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Going ahead to step 12:
21 goes into 120 5 times with a remainder of 15.
The number 5 becomes the next digit in our result. 
Result so far: 29286.714285
Deduct 105 from 120 and we're left 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.

Advancing to step 13:
150 divided by 21 is 7 with a remainder of 3.
Put 7 as the next digit of the answer. 
Result so far: 29286.7142857
Deduct 147 from 150 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

On to step 14:
21 can be fit into 30 1 times, resulting in a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 29286.71428571
If we take 21 away from 30, we end up 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.

After the division, we end up with 29286.71428571 and a remainder of 9e-09.