We divide 409440 by 21
We want to figure out the number of times 409440 can be divided by 21.

Moving on to step 1:
4 divided by 21 is 0 with a remainder of 4.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Include the next digit (0) from the dividend after 4, then repeat: 40 / 21

On to step 2:
21 goes into 40 1 times with a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Subtracting 21 from 40 leaves us with 19.
Bring next digit (9) of the dividend behind the 19 and repeat the process: 199 / 21

Let's proceed to step 3:
If we divide 199 by 21, we get 9 and a remainder of 10.
Use 9 as the next digit of our solution. 
Result so far: 19.0
Subtract 189 from 199 to get 10.
Fetch the next digit (4) from the dividend, attach it to 10 and continue: 104 / 21

Let's proceed to step 4:
21 can be fit into 104 4 times, resulting in a remainder of 20.
The next digit of our result is 4. 
Result so far: 194.0
The remainder is 20 after subtracting 84 from 104.
Append the next digit (4) from the dividend to 20 and continue with: 204 / 21

Advancing to step 5:
When dividing 204 by 21, we get 9 with a remainder of 15.
Use 9 as the next digit of our solution. 
Result so far: 1949.0
Subtract 189 from 204 to get 15.
Take the next digit (0) from the dividend and append it to 15, then repeat: 150 / 21

Going ahead to step 6:
The number 21 fits into 150 7 times, leaving a remainder of 3.
The next digit of our result is 7. 
Result so far: 19497.0
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.

Going ahead to step 7:
When dividing 30 by 21, we get 1 with a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 19497.1
Deduct 21 from 30 and we're left 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.

On to step 8:
When dividing 90 by 21, we get 4 with a remainder of 6.
Record the quotient 4 as the next digit in the result. 
Result so far: 19497.14
Subtracting 84 from 90 leaves us with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Advancing to step 9:
If we divide 60 by 21, we get 2 and a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 19497.142
The remainder is 18 after subtracting 42 from 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Step 10:
When dividing 180 by 21, we get 8 with a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 19497.1428
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.

Let's proceed to step 11:
When dividing 120 by 21, we get 5 with a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 19497.14285
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.

Moving on to step 12:
The number 21 fits into 150 7 times, leaving a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 19497.142857
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.

Going ahead to step 13:
When dividing 30 by 21, we get 1 with a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 19497.1428571
Deduct 21 from 30 and we're left 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.

On to step 14:
When dividing 90 by 21, we get 4 with a remainder of 6.
Record the quotient 4 as the next digit in the result. 
Result so far: 19497.14285714
Deduct 84 from 90 and we're left with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

After the division, we end up with 19497.14285714 and a remainder of 6e-09.