We look at the division of 43314 by 21 
The aim is to understand the frequency of 21 in 43314.

Advancing to step 1:
4 divided by 21 is 0 with a remainder of 4.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 4 to get 4.
Append the next digit (3) from the dividend to 4 and continue with: 43 / 21

Step 2:
If we divide 43 by 21, we get 2 and a remainder of 1.
Use 2 as the next digit of our solution. 
Result so far: 2.0
Deduct 42 from 43 and we're left with 1.
Include the next digit (3) from the dividend after 1, then repeat: 13 / 21

Going ahead to step 3:
If we divide 13 by 21, we get 0 and a remainder of 13.
Write down 0 as next digit of the result. 
Result so far: 20.0
Subtract 0 from 13 to get 13.
Include the next digit (1) from the dividend after 13, then repeat: 131 / 21

Step 4:
The number 21 fits into 131 6 times, leaving a remainder of 5.
Put 6 as the next digit of the answer. 
Result so far: 206.0
The remainder is 5 after subtracting 126 from 131.
Take the next digit (4) from the dividend and append it to 5, then repeat: 54 / 21

Moving on to step 5:
21 goes into 54 2 times with a remainder of 12.
Record the quotient 2 as the next digit in the result. 
Result so far: 2062.0
Subtract 42 from 54 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Going ahead to step 6:
120 divided by 21 is 5 with a remainder of 15.
Write down 5 as next digit of the result. 
Result so far: 2062.5
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.

Step 7:
21 goes into 150 7 times with a remainder of 3.
Write down 7 as next digit of the result. 
Result so far: 2062.57
The remainder is 3 after subtracting 147 from 150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 8:
When dividing 30 by 21, we get 1 with a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 2062.571
If we take 21 away from 30, we end up with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

On to step 9:
If we divide 90 by 21, we get 4 and a remainder of 6.
Put 4 as the next digit of the answer. 
Result so far: 2062.5714
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.

Step 10:
21 goes into 60 2 times with a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 2062.57142
Subtracting 42 from 60 leaves us 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.

Step 11:
The number 21 fits into 180 8 times, leaving a remainder of 12.
Use 8 as the next digit of our solution. 
Result so far: 2062.571428
Subtract 168 from 180 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 12:
The number 21 fits into 120 5 times, leaving a remainder of 15.
The number 5 becomes the next digit in our result. 
Result so far: 2062.5714285
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.

Going ahead to step 13:
When dividing 150 by 21, we get 7 with a remainder of 3.
The next digit of our result is 7. 
Result so far: 2062.57142857
Subtracting 147 from 150 leaves us with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Our division results in 2062.57142857 with a remaining 3e-09.