911884 divided by 21 
The aim is to understand the frequency of 21 in 911884.

On to step 1:
21 can be fit into 9 0 times, resulting in a remainder of 9.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 9, we end up with 9.
Append the next digit (1) from the dividend to 9 and continue with: 91 / 21

Advancing to step 2:
91 divided by 21 is 4 with a remainder of 7.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
Deduct 84 from 91 and we're left with 7.
Include the next digit (1) from the dividend after 7, then repeat: 71 / 21

Advancing to step 3:
The number 21 fits into 71 3 times, leaving a remainder of 8.
Use 3 as the next digit of our solution. 
Result so far: 43.0
If we subtract 63 from 71, we get 8.
Grab the next digit (8) from the dividend, add it to 8, then carry on: 88 / 21

Moving on to step 4:
21 can be fit into 88 4 times, resulting in a remainder of 4.
The number 4 becomes the next digit in our result. 
Result so far: 434.0
The remainder is 4 after subtracting 84 from 88.
Fetch the next digit (8) from the dividend, attach it to 4 and continue: 48 / 21

Moving on to step 5:
21 goes into 48 2 times with a remainder of 6.
The number 2 becomes the next digit in our result. 
Result so far: 4342.0
If we take 42 away from 48, we end up with 6.
Grab the next digit (4) from the dividend, add it to 6, then carry on: 64 / 21

Advancing to step 6:
21 goes into 64 3 times with a remainder of 1.
Put 3 as the next digit of the answer. 
Result so far: 43423.0
Deduct 63 from 64 and we're left with 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 7:
The number 21 fits into 10 0 times, leaving a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 43423.0
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.

Moving on to step 8:
The number 21 fits into 100 4 times, leaving a remainder of 16.
The number 4 becomes the next digit in our result. 
Result so far: 43423.04
If we subtract 84 from 100, 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.

On to step 9:
When dividing 160 by 21, we get 7 with a remainder of 13.
Put 7 as the next digit of the answer. 
Result so far: 43423.047
If we subtract 147 from 160, we get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Let's proceed to step 10:
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: 43423.0476
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 11:
21 goes into 40 1 times with a remainder of 19.
Write down 1 as next digit of the result. 
Result so far: 43423.04761
The remainder is 19 after subtracting 21 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Let's proceed to step 12:
190 divided by 21 is 9 with a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 43423.047619
If we take 189 away from 190, we end up with 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 13:
The number 21 fits into 10 0 times, leaving a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 43423.047619
If we take 0 away from 10, we end up 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.

On to step 14:
If we divide 100 by 21, we get 4 and a remainder of 16.
Use 4 as the next digit of our solution. 
Result so far: 43423.04761904
If we subtract 84 from 100, 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.

Our division results in 43423.04761904 with a remaining 1.6e-08.