Let's divide 682309 by 21
The aim is to understand the frequency of 21 in 682309.

Step 1:
When dividing 6 by 21, we get 0 with a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Fetch the next digit (8) from the dividend, attach it to 6 and continue: 68 / 21

Going ahead to step 2:
If we divide 68 by 21, we get 3 and a remainder of 5.
The number 3 becomes the next digit in our result. 
Result so far: 3.0
If we take 63 away from 68, we end up with 5.
Append the next digit (2) from the dividend to 5 and continue with: 52 / 21

Going ahead to step 3:
If we divide 52 by 21, we get 2 and a remainder of 10.
Use 2 as the next digit of our solution. 
Result so far: 32.0
If we subtract 42 from 52, we get 10.
Append the next digit (3) from the dividend to 10 and continue with: 103 / 21

Let's proceed to step 4:
The number 21 fits into 103 4 times, leaving a remainder of 19.
Write down 4 as next digit of the result. 
Result so far: 324.0
Deduct 84 from 103 and we're left with 19.
Grab the next digit (0) from the dividend, add it to 19, then carry on: 190 / 21

Moving on to step 5:
190 divided by 21 is 9 with a remainder of 1.
The next digit of our result is 9. 
Result so far: 3249.0
Subtract 189 from 190 to get 1.
Include the next digit (9) from the dividend after 1, then repeat: 19 / 21

Step 6:
21 goes into 19 0 times with a remainder of 19.
Record the quotient 0 as the next digit in the result. 
Result so far: 32490.0
Subtract 0 from 19 to get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

On to step 7:
21 can be fit into 190 9 times, resulting in a remainder of 1.
The next digit of our result is 9. 
Result so far: 32490.9
Subtract 189 from 190 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.

Going ahead to step 8:
If we divide 10 by 21, we get 0 and a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 32490.9
Subtract 0 from 10 to 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.

Let's proceed to step 9:
100 divided by 21 is 4 with a remainder of 16.
Write down 4 as next digit of the result. 
Result so far: 32490.904
If we take 84 away from 100, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

On to step 10:
160 divided by 21 is 7 with a remainder of 13.
The next digit of our result is 7. 
Result so far: 32490.9047
Deduct 147 from 160 and we're left with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

On to step 11:
130 divided by 21 is 6 with a remainder of 4.
The next digit of our result is 6. 
Result so far: 32490.90476
Subtracting 126 from 130 leaves us with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 12:
If we divide 40 by 21, we get 1 and a remainder of 19.
Write down 1 as next digit of the result. 
Result so far: 32490.904761
Subtracting 21 from 40 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Step 13:
The number 21 fits into 190 9 times, leaving a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 32490.9047619
If we subtract 189 from 190, we 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.

On to step 14:
21 can be fit into 10 0 times, resulting in a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 32490.9047619
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.

After the division, we end up with 32490.9047619 and a remainder of 1e-08.