We look at the division of 795218 by 21 
The aim is to understand the frequency of 21 in 795218.

Moving on to step 1:
The number 21 fits into 7 0 times, leaving a remainder of 7.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 7, we end up with 7.
Include the next digit (9) from the dividend after 7, then repeat: 79 / 21

Advancing to step 2:
When dividing 79 by 21, we get 3 with a remainder of 16.
The next digit of our result is 3. 
Result so far: 3.0
Subtracting 63 from 79 leaves us with 16.
Include the next digit (5) from the dividend after 16, then repeat: 165 / 21

On to step 3:
The number 21 fits into 165 7 times, leaving a remainder of 18.
Record the quotient 7 as the next digit in the result. 
Result so far: 37.0
Subtract 147 from 165 to get 18.
Bring next digit (2) of the dividend behind the 18 and repeat the process: 182 / 21

Let's proceed to step 4:
If we divide 182 by 21, we get 8 and a remainder of 14.
The number 8 becomes the next digit in our result. 
Result so far: 378.0
If we subtract 168 from 182, we get 14.
Append the next digit (1) from the dividend to 14 and continue with: 141 / 21

Going ahead to step 5:
If we divide 141 by 21, we get 6 and a remainder of 15.
The number 6 becomes the next digit in our result. 
Result so far: 3786.0
The remainder is 15 after subtracting 126 from 141.
Bring next digit (8) of the dividend behind the 15 and repeat the process: 158 / 21

Step 6:
21 goes into 158 7 times with a remainder of 11.
Record the quotient 7 as the next digit in the result. 
Result so far: 37867.0
Subtract 147 from 158 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.

Step 7:
21 can be fit into 110 5 times, resulting in a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 37867.5
Deduct 105 from 110 and we're left 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 8:
21 can be fit into 50 2 times, resulting in a remainder of 8.
Use 2 as the next digit of our solution. 
Result so far: 37867.52
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.

On to step 9:
When dividing 80 by 21, we get 3 with a remainder of 17.
The next digit of our result is 3. 
Result so far: 37867.523
If we take 63 away from 80, we end up 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.

Advancing to step 10:
When dividing 170 by 21, we get 8 with a remainder of 2.
Use 8 as the next digit of our solution. 
Result so far: 37867.5238
Deduct 168 from 170 and we're left 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 11:
21 can be fit into 20 0 times, resulting in a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 37867.5238
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 12:
When dividing 200 by 21, we get 9 with a remainder of 11.
The next digit of our result is 9. 
Result so far: 37867.523809
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.

Let's proceed to step 13:
When dividing 110 by 21, we get 5 with a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 37867.5238095
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.

Moving on to step 14:
When dividing 50 by 21, we get 2 with a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 37867.52380952
Deduct 42 from 50 and we're left 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.

Our division results in 37867.52380952 with a remaining 8e-09.