We're dividing 127864 by 21 
The aim is to understand the frequency of 21 in 127864.

Step 1:
21 goes into 1 0 times with a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Append the next digit (2) from the dividend to 1 and continue with: 12 / 21

Going ahead to step 2:
If we divide 12 by 21, we get 0 and a remainder of 12.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 12 to get 12.
Grab the next digit (7) from the dividend, add it to 12, then carry on: 127 / 21

Let's proceed to step 3:
If we divide 127 by 21, we get 6 and a remainder of 1.
The number 6 becomes the next digit in our result. 
Result so far: 6.0
The remainder is 1 after subtracting 126 from 127.
Take the next digit (8) from the dividend and append it to 1, then repeat: 18 / 21

Let's proceed to step 4:
The number 21 fits into 18 0 times, leaving a remainder of 18.
Record the quotient 0 as the next digit in the result. 
Result so far: 60.0
Deduct 0 from 18 and we're left with 18.
Fetch the next digit (6) from the dividend, attach it to 18 and continue: 186 / 21

Going ahead to step 5:
21 goes into 186 8 times with a remainder of 18.
Use 8 as the next digit of our solution. 
Result so far: 608.0
The remainder is 18 after subtracting 168 from 186.
Include the next digit (4) from the dividend after 18, then repeat: 184 / 21

Let's proceed to step 6:
If we divide 184 by 21, we get 8 and a remainder of 16.
Record the quotient 8 as the next digit in the result. 
Result so far: 6088.0
If we subtract 168 from 184, we 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 7:
The number 21 fits into 160 7 times, leaving a remainder of 13.
The next digit of our result is 7. 
Result so far: 6088.7
The remainder is 13 after subtracting 147 from 160.
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 8:
When dividing 130 by 21, we get 6 with a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 6088.76
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.

Step 9:
40 divided by 21 is 1 with a remainder of 19.
Put 1 as the next digit of the answer. 
Result so far: 6088.761
Subtract 21 from 40 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 10:
190 divided by 21 is 9 with a remainder of 1.
Put 9 as the next digit of the answer. 
Result so far: 6088.7619
The remainder is 1 after subtracting 189 from 190.
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 11:
21 can be fit into 10 0 times, resulting in a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 6088.7619
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.

Moving on to step 12:
21 can be fit into 100 4 times, resulting in a remainder of 16.
Record the quotient 4 as the next digit in the result. 
Result so far: 6088.761904
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 13:
160 divided by 21 is 7 with a remainder of 13.
The next digit of our result is 7. 
Result so far: 6088.7619047
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.

Advancing to step 14:
130 divided by 21 is 6 with a remainder of 4.
Use 6 as the next digit of our solution. 
Result so far: 6088.76190476
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.

The final outcome is 6088.76190476, with a leftover of 4e-09.