We look at the division of 82436 by 21 
The aim is to understand the frequency of 21 in 82436.

On to step 1:
21 goes into 8 0 times with a remainder of 8.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 8 to get 8.
Fetch the next digit (2) from the dividend, attach it to 8 and continue: 82 / 21

Advancing to step 2:
82 divided by 21 is 3 with a remainder of 19.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
If we subtract 63 from 82, we get 19.
Append the next digit (4) from the dividend to 19 and continue with: 194 / 21

Let's proceed to step 3:
21 goes into 194 9 times with a remainder of 5.
The next digit of our result is 9. 
Result so far: 39.0
If we take 189 away from 194, we end up with 5.
Grab the next digit (3) from the dividend, add it to 5, then carry on: 53 / 21

Going ahead to step 4:
21 can be fit into 53 2 times, resulting in a remainder of 11.
Put 2 as the next digit of the answer. 
Result so far: 392.0
Subtract 42 from 53 to get 11.
Grab the next digit (6) from the dividend, add it to 11, then carry on: 116 / 21

On to step 5:
The number 21 fits into 116 5 times, leaving a remainder of 11.
Use 5 as the next digit of our solution. 
Result so far: 3925.0
Subtract 105 from 116 to get 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 6:
If we divide 110 by 21, we get 5 and a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 3925.5
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.

Advancing to step 7:
If we divide 50 by 21, we get 2 and a remainder of 8.
The next digit of our result is 2. 
Result so far: 3925.52
If we subtract 42 from 50, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

On to step 8:
If we divide 80 by 21, we get 3 and a remainder of 17.
Use 3 as the next digit of our solution. 
Result so far: 3925.523
Subtract 63 from 80 to get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Advancing to step 9:
When dividing 170 by 21, we get 8 with a remainder of 2.
Write down 8 as next digit of the result. 
Result so far: 3925.5238
Subtracting 168 from 170 leaves us with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Advancing to step 10:
21 can be fit into 20 0 times, resulting in a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 3925.5238
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.

On to step 11:
200 divided by 21 is 9 with a remainder of 11.
Record the quotient 9 as the next digit in the result. 
Result so far: 3925.523809
If we subtract 189 from 200, we get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 12:
110 divided by 21 is 5 with a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 3925.5238095
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.

Going ahead to step 13:
50 divided by 21 is 2 with a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 3925.52380952
The remainder is 8 after subtracting 42 from 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

In conclusion, the division gives 3925.52380952 with a balance of 8e-09.