Let's divide 115888 by 21
The aim is to understand the frequency of 21 in 115888.

Going ahead to step 1:
The number 21 fits into 1 0 times, leaving a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 1 to get 1.
Include the next digit (1) from the dividend after 1, then repeat: 11 / 21

Moving on to step 2:
The number 21 fits into 11 0 times, leaving a remainder of 11.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 11 to get 11.
Grab the next digit (5) from the dividend, add it to 11, then carry on: 115 / 21

Moving on to step 3:
115 divided by 21 is 5 with a remainder of 10.
Record the quotient 5 as the next digit in the result. 
Result so far: 5.0
Subtract 105 from 115 to get 10.
Bring next digit (8) of the dividend behind the 10 and repeat the process: 108 / 21

Let's proceed to step 4:
21 can be fit into 108 5 times, resulting in a remainder of 3.
Use 5 as the next digit of our solution. 
Result so far: 55.0
Subtract 105 from 108 to get 3.
Append the next digit (8) from the dividend to 3 and continue with: 38 / 21

Step 5:
If we divide 38 by 21, we get 1 and a remainder of 17.
Record the quotient 1 as the next digit in the result. 
Result so far: 551.0
If we take 21 away from 38, we end up with 17.
Include the next digit (8) from the dividend after 17, then repeat: 178 / 21

Step 6:
The number 21 fits into 178 8 times, leaving a remainder of 10.
Put 8 as the next digit of the answer. 
Result so far: 5518.0
The remainder is 10 after subtracting 168 from 178.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

On to step 7:
21 goes into 100 4 times with a remainder of 16.
Put 4 as the next digit of the answer. 
Result so far: 5518.4
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.

Going ahead to step 8:
The number 21 fits into 160 7 times, leaving a remainder of 13.
The next digit of our result is 7. 
Result so far: 5518.47
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 9:
When dividing 130 by 21, we get 6 with a remainder of 4.
Record the quotient 6 as the next digit in the result. 
Result so far: 5518.476
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 10:
21 goes into 40 1 times with a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 5518.4761
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.

On to step 11:
If we divide 190 by 21, we get 9 and a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 5518.47619
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.

Moving on to step 12:
21 can be fit into 10 0 times, resulting in a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 5518.47619
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.

Advancing to step 13:
100 divided by 21 is 4 with a remainder of 16.
Record the quotient 4 as the next digit in the result. 
Result so far: 5518.4761904
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 14:
160 divided by 21 is 7 with a remainder of 13.
Use 7 as the next digit of our solution. 
Result so far: 5518.47619047
Subtracting 147 from 160 leaves us 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.

The final result is 5518.47619047 with a remainder of 1.3e-08.