We look at the division of 270933 by 21 
The aim is to understand the frequency of 21 in 270933.

Moving on to step 1:
21 can be fit into 2 0 times, resulting in a remainder of 2.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 2, we end up with 2.
Bring next digit (7) of the dividend behind the 2 and repeat the process: 27 / 21

Let's proceed to step 2:
When dividing 27 by 21, we get 1 with a remainder of 6.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Subtract 21 from 27 to get 6.
Grab the next digit (0) from the dividend, add it to 6, then carry on: 60 / 21

Moving on to step 3:
21 can be fit into 60 2 times, resulting in a remainder of 18.
Put 2 as the next digit of the answer. 
Result so far: 12.0
If we take 42 away from 60, we end up with 18.
Include the next digit (9) from the dividend after 18, then repeat: 189 / 21

Advancing to step 4:
189 divided by 21 is 9 with a remainder of 0.
The number 9 becomes the next digit in our result. 
Result so far: 129.0
If we subtract 189 from 189, we get 0.
Fetch the next digit (3) from the dividend, attach it to 0 and continue: 3 / 21

Moving on to step 5:
21 goes into 3 0 times with a remainder of 3.
Write down 0 as next digit of the result. 
Result so far: 1290.0
If we take 0 away from 3, we end up with 3.
Take the next digit (3) from the dividend and append it to 3, then repeat: 33 / 21

On to step 6:
33 divided by 21 is 1 with a remainder of 12.
Write down 1 as next digit of the result. 
Result so far: 12901.0
If we take 21 away from 33, we end up with 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 7:
When dividing 120 by 21, we get 5 with a remainder of 15.
The next digit of our result is 5. 
Result so far: 12901.5
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.

On to step 8:
21 can be fit into 150 7 times, resulting in a remainder of 3.
The number 7 becomes the next digit in our result. 
Result so far: 12901.57
Subtract 147 from 150 to get 3.
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 9:
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: 12901.571
Deduct 21 from 30 and we're left 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.

Let's proceed to step 10:
21 can be fit into 90 4 times, resulting in a remainder of 6.
Record the quotient 4 as the next digit in the result. 
Result so far: 12901.5714
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 11:
21 goes into 60 2 times with a remainder of 18.
The next digit of our result is 2. 
Result so far: 12901.57142
If we subtract 42 from 60, we get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

On to step 12:
The number 21 fits into 180 8 times, leaving a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 12901.571428
Subtracting 168 from 180 leaves us with 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 13:
If we divide 120 by 21, we get 5 and a remainder of 15.
The number 5 becomes the next digit in our result. 
Result so far: 12901.5714285
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.

On to step 14:
21 can be fit into 150 7 times, resulting in a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 12901.57142857
Subtract 147 from 150 to get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

The final outcome is 12901.57142857, with a leftover of 3e-09.