We're dividing 844551 by 21 
The aim is to understand the frequency of 21 in 844551.

Moving on to step 1:
21 can be fit into 8 0 times, resulting in a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 8 to get 8.
Grab the next digit (4) from the dividend, add it to 8, then carry on: 84 / 21

Step 2:
When dividing 84 by 21, we get 4 with a remainder of 0.
Use 4 as the next digit of our solution. 
Result so far: 4.0
If we subtract 84 from 84, we get 0.
Append the next digit (4) from the dividend to 0 and continue with: 4 / 21

Advancing to step 3:
21 can be fit into 4 0 times, resulting in a remainder of 4.
Record the quotient 0 as the next digit in the result. 
Result so far: 40.0
The remainder is 4 after subtracting 0 from 4.
Bring next digit (5) of the dividend behind the 4 and repeat the process: 45 / 21

Going ahead to step 4:
21 goes into 45 2 times with a remainder of 3.
The number 2 becomes the next digit in our result. 
Result so far: 402.0
The remainder is 3 after subtracting 42 from 45.
Bring next digit (5) of the dividend behind the 3 and repeat the process: 35 / 21

Step 5:
When dividing 35 by 21, we get 1 with a remainder of 14.
The number 1 becomes the next digit in our result. 
Result so far: 4021.0
If we subtract 21 from 35, we get 14.
Grab the next digit (1) from the dividend, add it to 14, then carry on: 141 / 21

On to step 6:
If we divide 141 by 21, we get 6 and a remainder of 15.
Write down 6 as next digit of the result. 
Result so far: 40216.0
If we subtract 126 from 141, we get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Advancing to step 7:
If we divide 150 by 21, we get 7 and a remainder of 3.
Put 7 as the next digit of the answer. 
Result so far: 40216.7
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.

On to step 8:
If we divide 30 by 21, we get 1 and a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 40216.71
If we subtract 21 from 30, we get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

On to step 9:
90 divided by 21 is 4 with a remainder of 6.
The next digit of our result is 4. 
Result so far: 40216.714
Subtract 84 from 90 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Let's proceed to step 10:
21 can be fit into 60 2 times, resulting in a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 40216.7142
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.

Going ahead to step 11:
The number 21 fits into 180 8 times, leaving a remainder of 12.
Write down 8 as next digit of the result. 
Result so far: 40216.71428
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.

Advancing to step 12:
When dividing 120 by 21, we get 5 with a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 40216.714285
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.

Going ahead to step 13:
When dividing 150 by 21, we get 7 with a remainder of 3.
Use 7 as the next digit of our solution. 
Result so far: 40216.7142857
If we subtract 147 from 150, we 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.

Moving on to step 14:
21 goes into 30 1 times with a remainder of 9.
Write down 1 as next digit of the result. 
Result so far: 40216.71428571
If we subtract 21 from 30, we get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

The final outcome is 40216.71428571, with a leftover of 9e-09.