We divide 823596 by 21
The aim is to understand the frequency of 21 in 823596.

Moving on to step 1:
21 goes into 8 0 times with a remainder of 8.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Include the next digit (2) from the dividend after 8, then repeat: 82 / 21

Step 2:
82 divided by 21 is 3 with a remainder of 19.
Write down 3 as next digit of the result. 
Result so far: 3.0
Subtracting 63 from 82 leaves us with 19.
Bring next digit (3) of the dividend behind the 19 and repeat the process: 193 / 21

Advancing to step 3:
When dividing 193 by 21, we get 9 with a remainder of 4.
The number 9 becomes the next digit in our result. 
Result so far: 39.0
Subtract 189 from 193 to get 4.
Include the next digit (5) from the dividend after 4, then repeat: 45 / 21

Moving on to step 4:
The number 21 fits into 45 2 times, leaving a remainder of 3.
Put 2 as the next digit of the answer. 
Result so far: 392.0
The remainder is 3 after subtracting 42 from 45.
Fetch the next digit (9) from the dividend, attach it to 3 and continue: 39 / 21

Advancing to step 5:
The number 21 fits into 39 1 times, leaving a remainder of 18.
Put 1 as the next digit of the answer. 
Result so far: 3921.0
If we subtract 21 from 39, we get 18.
Grab the next digit (6) from the dividend, add it to 18, then carry on: 186 / 21

Going ahead to step 6:
21 goes into 186 8 times with a remainder of 18.
Use 8 as the next digit of our solution. 
Result so far: 39218.0
Deduct 168 from 186 and we're left 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.

Let's proceed to step 7:
If we divide 180 by 21, we get 8 and a remainder of 12.
Write down 8 as next digit of the result. 
Result so far: 39218.8
The remainder is 12 after subtracting 168 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 8:
21 can be fit into 120 5 times, resulting in a remainder of 15.
Write down 5 as next digit of the result. 
Result so far: 39218.85
Deduct 105 from 120 and we're left with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Step 9:
21 goes into 150 7 times with a remainder of 3.
The next digit of our result is 7. 
Result so far: 39218.857
If we subtract 147 from 150, we get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Moving on to step 10:
30 divided by 21 is 1 with a remainder of 9.
Write down 1 as next digit of the result. 
Result so far: 39218.8571
Subtract 21 from 30 to get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Going ahead to step 11:
90 divided by 21 is 4 with a remainder of 6.
Use 4 as the next digit of our solution. 
Result so far: 39218.85714
Deduct 84 from 90 and we're left 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.

Going ahead to step 12:
If we divide 60 by 21, we get 2 and a remainder of 18.
Record the quotient 2 as the next digit in the result. 
Result so far: 39218.857142
Subtract 42 from 60 to get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Advancing to step 13:
21 can be fit into 180 8 times, resulting in a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 39218.8571428
The remainder is 12 after subtracting 168 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

On to step 14:
If we divide 120 by 21, we get 5 and a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 39218.85714285
Subtracting 105 from 120 leaves us with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

The final outcome is 39218.85714285, with a leftover of 1.5e-08.