Let's divide 424223 by 21
The aim is to understand the frequency of 21 in 424223.

Moving on to step 1:
21 goes into 4 0 times with a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 4 and we're left with 4.
Take the next digit (2) from the dividend and append it to 4, then repeat: 42 / 21

Going ahead to step 2:
If we divide 42 by 21, we get 2 and a remainder of 0.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
The remainder is 0 after subtracting 42 from 42.
Append the next digit (4) from the dividend to 0 and continue with: 4 / 21

Step 3:
21 goes into 4 0 times with a remainder of 4.
The next digit of our result is 0. 
Result so far: 20.0
Subtract 0 from 4 to get 4.
Include the next digit (2) from the dividend after 4, then repeat: 42 / 21

Moving on to step 4:
21 can be fit into 42 2 times, resulting in a remainder of 0.
Put 2 as the next digit of the answer. 
Result so far: 202.0
If we take 42 away from 42, we end up with 0.
Bring next digit (2) of the dividend behind the 0 and repeat the process: 2 / 21

On to step 5:
If we divide 2 by 21, we get 0 and a remainder of 2.
Write down 0 as next digit of the result. 
Result so far: 2020.0
The remainder is 2 after subtracting 0 from 2.
Append the next digit (3) from the dividend to 2 and continue with: 23 / 21

Advancing to step 6:
21 goes into 23 1 times with a remainder of 2.
Put 1 as the next digit of the answer. 
Result so far: 20201.0
Subtracting 21 from 23 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.

Step 7:
20 divided by 21 is 0 with a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 20201.0
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.

On to step 8:
When dividing 200 by 21, we get 9 with a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 20201.09
Subtract 189 from 200 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.

Advancing to step 9:
21 can be fit into 110 5 times, resulting in a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 20201.095
Subtracting 105 from 110 leaves us 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.

Moving on to step 10:
If we divide 50 by 21, we get 2 and a remainder of 8.
Record the quotient 2 as the next digit in the result. 
Result so far: 20201.0952
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.

Moving on to step 11:
21 goes into 80 3 times with a remainder of 17.
Write down 3 as next digit of the result. 
Result so far: 20201.09523
Deduct 63 from 80 and we're left with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Step 12:
The number 21 fits into 170 8 times, leaving a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 20201.095238
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.

Let's proceed to step 13:
The number 21 fits into 20 0 times, leaving a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 20201.095238
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 14:
200 divided by 21 is 9 with a remainder of 11.
Put 9 as the next digit of the answer. 
Result so far: 20201.09523809
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.

The final result is 20201.09523809 with a remainder of 1.1e-08.