We look at the division of 930784 by 21 
The aim is to understand the frequency of 21 in 930784.

Step 1:
If we divide 9 by 21, we get 0 and a remainder of 9.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 9 after subtracting 0 from 9.
Fetch the next digit (3) from the dividend, attach it to 9 and continue: 93 / 21

On to step 2:
When dividing 93 by 21, we get 4 with a remainder of 9.
The next digit of our result is 4. 
Result so far: 4.0
Subtract 84 from 93 to get 9.
Include the next digit (0) from the dividend after 9, then repeat: 90 / 21

Step 3:
If we divide 90 by 21, we get 4 and a remainder of 6.
Use 4 as the next digit of our solution. 
Result so far: 44.0
If we take 84 away from 90, we end up with 6.
Grab the next digit (7) from the dividend, add it to 6, then carry on: 67 / 21

On to step 4:
When dividing 67 by 21, we get 3 with a remainder of 4.
Write down 3 as next digit of the result. 
Result so far: 443.0
Deduct 63 from 67 and we're left with 4.
Include the next digit (8) from the dividend after 4, then repeat: 48 / 21

Moving on to step 5:
48 divided by 21 is 2 with a remainder of 6.
Write down 2 as next digit of the result. 
Result so far: 4432.0
The remainder is 6 after subtracting 42 from 48.
Grab the next digit (4) from the dividend, add it to 6, then carry on: 64 / 21

Going ahead to step 6:
21 goes into 64 3 times with a remainder of 1.
Record the quotient 3 as the next digit in the result. 
Result so far: 44323.0
Subtract 63 from 64 to get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Moving on to step 7:
21 can be fit into 10 0 times, resulting in a remainder of 10.
The next digit of our result is 0. 
Result so far: 44323.0
Deduct 0 from 10 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 8:
The number 21 fits into 100 4 times, leaving a remainder of 16.
The number 4 becomes the next digit in our result. 
Result so far: 44323.04
Subtract 84 from 100 to get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Let's proceed to step 9:
If we divide 160 by 21, we get 7 and a remainder of 13.
Put 7 as the next digit of the answer. 
Result so far: 44323.047
If we subtract 147 from 160, we get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Going ahead to step 10:
21 can be fit into 130 6 times, resulting in a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 44323.0476
If we subtract 126 from 130, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

On to step 11:
21 goes into 40 1 times with a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 44323.04761
The remainder is 19 after subtracting 21 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Advancing to step 12:
The number 21 fits into 190 9 times, leaving a remainder of 1.
Record the quotient 9 as the next digit in the result. 
Result so far: 44323.047619
If we take 189 away from 190, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Going ahead to step 13:
If we divide 10 by 21, we get 0 and a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 44323.047619
If we subtract 0 from 10, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Step 14:
100 divided by 21 is 4 with a remainder of 16.
Put 4 as the next digit of the answer. 
Result so far: 44323.04761904
Subtract 84 from 100 to get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

After the division, we end up with 44323.04761904 and a remainder of 1.6e-08.