82424 ÷ 21 
The aim is to understand the frequency of 21 in 82424.

On to step 1:
When dividing 8 by 21, we get 0 with a remainder of 8.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Fetch the next digit (2) from the dividend, attach it to 8 and continue: 82 / 21

Advancing to step 2:
21 goes into 82 3 times with a remainder of 19.
Write down 3 as next digit of the result. 
Result so far: 3.0
Subtract 63 from 82 to get 19.
Include the next digit (4) from the dividend after 19, then repeat: 194 / 21

On to step 3:
When dividing 194 by 21, we get 9 with a remainder of 5.
The next digit of our result is 9. 
Result so far: 39.0
Subtracting 189 from 194 leaves us with 5.
Fetch the next digit (2) from the dividend, attach it to 5 and continue: 52 / 21

On to step 4:
21 can be fit into 52 2 times, resulting in a remainder of 10.
The number 2 becomes the next digit in our result. 
Result so far: 392.0
Deduct 42 from 52 and we're left with 10.
Fetch the next digit (4) from the dividend, attach it to 10 and continue: 104 / 21

Step 5:
21 goes into 104 4 times with a remainder of 20.
The next digit of our result is 4. 
Result so far: 3924.0
Subtracting 84 from 104 leaves us with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Going ahead to step 6:
When dividing 200 by 21, we get 9 with a remainder of 11.
The number 9 becomes the next digit in our result. 
Result so far: 3924.9
If we take 189 away from 200, we end up with 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 7:
110 divided by 21 is 5 with a remainder of 5.
The next digit of our result is 5. 
Result so far: 3924.95
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 8:
If we divide 50 by 21, we get 2 and a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 3924.952
If we take 42 away from 50, we end up with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Let's proceed to step 9:
If we divide 80 by 21, we get 3 and a remainder of 17.
The next digit of our result is 3. 
Result so far: 3924.9523
The remainder is 17 after subtracting 63 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Let's proceed to step 10:
21 goes into 170 8 times with a remainder of 2.
Use 8 as the next digit of our solution. 
Result so far: 3924.95238
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 11:
21 can be fit into 20 0 times, resulting in a remainder of 20.
Write down 0 as next digit of the result. 
Result so far: 3924.95238
Deduct 0 from 20 and we're left with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Let's proceed to step 12:
The number 21 fits into 200 9 times, leaving a remainder of 11.
Put 9 as the next digit of the answer. 
Result so far: 3924.9523809
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.

On to step 13:
The number 21 fits into 110 5 times, leaving a remainder of 5.
Use 5 as the next digit of our solution. 
Result so far: 3924.95238095
If we subtract 105 from 110, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

After the division, we end up with 3924.95238095 and a remainder of 5e-09.