We're dividing 306697 by 21 
The aim is to understand the frequency of 21 in 306697.

Going ahead to step 1:
If we divide 3 by 21, we get 0 and a remainder of 3.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 3 after subtracting 0 from 3.
Grab the next digit (0) from the dividend, add it to 3, then carry on: 30 / 21

Step 2:
If we divide 30 by 21, we get 1 and a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
Deduct 21 from 30 and we're left with 9.
Bring next digit (6) of the dividend behind the 9 and repeat the process: 96 / 21

Let's proceed to step 3:
96 divided by 21 is 4 with a remainder of 12.
The next digit of our result is 4. 
Result so far: 14.0
If we subtract 84 from 96, we get 12.
Take the next digit (6) from the dividend and append it to 12, then repeat: 126 / 21

Advancing to step 4:
When dividing 126 by 21, we get 6 with a remainder of 0.
The number 6 becomes the next digit in our result. 
Result so far: 146.0
The remainder is 0 after subtracting 126 from 126.
Grab the next digit (9) from the dividend, add it to 0, then carry on: 9 / 21

Advancing to step 5:
21 goes into 9 0 times with a remainder of 9.
The number 0 becomes the next digit in our result. 
Result so far: 1460.0
If we subtract 0 from 9, we get 9.
Append the next digit (7) from the dividend to 9 and continue with: 97 / 21

Let's proceed to step 6:
97 divided by 21 is 4 with a remainder of 13.
Record the quotient 4 as the next digit in the result. 
Result so far: 14604.0
Deduct 84 from 97 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 7:
130 divided by 21 is 6 with a remainder of 4.
The number 6 becomes the next digit in our result. 
Result so far: 14604.6
The remainder is 4 after subtracting 126 from 130.
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 8:
40 divided by 21 is 1 with a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 14604.61
If we take 21 away from 40, we end up 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.

Moving on to step 9:
21 can be fit into 190 9 times, resulting in a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 14604.619
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.

Moving on to step 10:
21 goes into 10 0 times with a remainder of 10.
The next digit of our result is 0. 
Result so far: 14604.619
Subtracting 0 from 10 leaves us 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.

Step 11:
The number 21 fits into 100 4 times, leaving a remainder of 16.
Record the quotient 4 as the next digit in the result. 
Result so far: 14604.61904
Deduct 84 from 100 and we're left 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.

Advancing to step 12:
21 goes into 160 7 times with a remainder of 13.
Write down 7 as next digit of the result. 
Result so far: 14604.619047
If we take 147 away from 160, we end up 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.

Advancing to step 13:
The number 21 fits into 130 6 times, leaving a remainder of 4.
Use 6 as the next digit of our solution. 
Result so far: 14604.6190476
If we take 126 away from 130, we end up 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.

On to step 14:
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: 14604.61904761
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.

Our division results in 14604.61904761 with a remaining 1.9e-08.