732720 divided by 21 
The aim is to understand the frequency of 21 in 732720.

Going ahead to step 1:
7 divided by 21 is 0 with a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 7 leaves us with 7.
Grab the next digit (3) from the dividend, add it to 7, then carry on: 73 / 21

On to step 2:
73 divided by 21 is 3 with a remainder of 10.
Write down 3 as next digit of the result. 
Result so far: 3.0
If we take 63 away from 73, we end up with 10.
Take the next digit (2) from the dividend and append it to 10, then repeat: 102 / 21

Let's proceed to step 3:
If we divide 102 by 21, we get 4 and a remainder of 18.
Use 4 as the next digit of our solution. 
Result so far: 34.0
Subtracting 84 from 102 leaves us with 18.
Fetch the next digit (7) from the dividend, attach it to 18 and continue: 187 / 21

Going ahead to step 4:
187 divided by 21 is 8 with a remainder of 19.
The next digit of our result is 8. 
Result so far: 348.0
Subtract 168 from 187 to get 19.
Grab the next digit (2) from the dividend, add it to 19, then carry on: 192 / 21

Step 5:
The number 21 fits into 192 9 times, leaving a remainder of 3.
Use 9 as the next digit of our solution. 
Result so far: 3489.0
If we take 189 away from 192, we end up with 3.
Take the next digit (0) from the dividend and append it to 3, then repeat: 30 / 21

On to step 6:
30 divided by 21 is 1 with a remainder of 9.
The next digit of our result is 1. 
Result so far: 34891.0
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.

Moving on to step 7:
21 can be fit into 90 4 times, resulting in a remainder of 6.
Use 4 as the next digit of our solution. 
Result so far: 34891.4
Subtract 84 from 90 to 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.

Advancing to step 8:
21 goes into 60 2 times with a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 34891.42
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 9:
21 goes into 180 8 times with a remainder of 12.
Write down 8 as next digit of the result. 
Result so far: 34891.428
Deduct 168 from 180 and we're left 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 10:
If we divide 120 by 21, we get 5 and a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 34891.4285
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.

On to step 11:
150 divided by 21 is 7 with a remainder of 3.
Use 7 as the next digit of our solution. 
Result so far: 34891.42857
Subtracting 147 from 150 leaves us 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 12:
21 goes into 30 1 times with a remainder of 9.
The next digit of our result is 1. 
Result so far: 34891.428571
Subtracting 21 from 30 leaves us 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 13:
If we divide 90 by 21, we get 4 and a remainder of 6.
Use 4 as the next digit of our solution. 
Result so far: 34891.4285714
If we take 84 away from 90, we end up 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.

Step 14:
21 goes into 60 2 times with a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 34891.42857142
Subtracting 42 from 60 leaves us with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

After the division, we end up with 34891.42857142 and a remainder of 1.8e-08.