We look at the division of 724240 by 21 
We want to figure out the number of times 724240 can be divided by 21.

Going ahead to step 1:
7 divided by 21 is 0 with a remainder of 7.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 7, we get 7.
Grab the next digit (2) from the dividend, add it to 7, then carry on: 72 / 21

Moving on to step 2:
21 goes into 72 3 times with a remainder of 9.
Put 3 as the next digit of the answer. 
Result so far: 3.0
Subtracting 63 from 72 leaves us with 9.
Bring next digit (4) of the dividend behind the 9 and repeat the process: 94 / 21

On to step 3:
If we divide 94 by 21, we get 4 and a remainder of 10.
Put 4 as the next digit of the answer. 
Result so far: 34.0
Deduct 84 from 94 and we're left with 10.
Include the next digit (2) from the dividend after 10, then repeat: 102 / 21

Moving on to step 4:
21 goes into 102 4 times with a remainder of 18.
Put 4 as the next digit of the answer. 
Result so far: 344.0
The remainder is 18 after subtracting 84 from 102.
Take the next digit (4) from the dividend and append it to 18, then repeat: 184 / 21

Let's proceed to step 5:
If we divide 184 by 21, we get 8 and a remainder of 16.
The next digit of our result is 8. 
Result so far: 3448.0
If we take 168 away from 184, we end up with 16.
Take the next digit (0) from the dividend and append it to 16, then repeat: 160 / 21

Going ahead to step 6:
When dividing 160 by 21, we get 7 with a remainder of 13.
Write down 7 as next digit of the result. 
Result so far: 34487.0
The remainder is 13 after subtracting 147 from 160.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Let's proceed to step 7:
The number 21 fits into 130 6 times, leaving a remainder of 4.
Put 6 as the next digit of the answer. 
Result so far: 34487.6
Subtracting 126 from 130 leaves us with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 8:
If we divide 40 by 21, we get 1 and a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 34487.61
Subtract 21 from 40 to get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Let's proceed to step 9:
The number 21 fits into 190 9 times, leaving a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 34487.619
Deduct 189 from 190 and we're left with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Advancing to step 10:
21 goes into 10 0 times with a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 34487.619
Deduct 0 from 10 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 11:
100 divided by 21 is 4 with a remainder of 16.
Use 4 as the next digit of our solution. 
Result so far: 34487.61904
The remainder is 16 after subtracting 84 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Step 12:
If we divide 160 by 21, we get 7 and a remainder of 13.
The next digit of our result is 7. 
Result so far: 34487.619047
Deduct 147 from 160 and we're left with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Advancing to step 13:
21 goes into 130 6 times with a remainder of 4.
Use 6 as the next digit of our solution. 
Result so far: 34487.6190476
If we take 126 away from 130, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 14:
The number 21 fits into 40 1 times, leaving a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 34487.61904761
Subtracting 21 from 40 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

In conclusion, the division gives 34487.61904761 with a balance of 1.9e-08.