We're dividing 849965 by 21 
The aim is to understand the frequency of 21 in 849965.

Moving on to step 1:
If we divide 8 by 21, we get 0 and a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Fetch the next digit (4) from the dividend, attach it to 8 and continue: 84 / 21

Advancing to step 2:
The number 21 fits into 84 4 times, leaving a remainder of 0.
Write down 4 as next digit of the result. 
Result so far: 4.0
Subtracting 84 from 84 leaves us with 0.
Append the next digit (9) from the dividend to 0 and continue with: 9 / 21

Advancing to step 3:
21 can be fit into 9 0 times, resulting in a remainder of 9.
Write down 0 as next digit of the result. 
Result so far: 40.0
If we subtract 0 from 9, we get 9.
Include the next digit (9) from the dividend after 9, then repeat: 99 / 21

Step 4:
21 goes into 99 4 times with a remainder of 15.
Write down 4 as next digit of the result. 
Result so far: 404.0
If we subtract 84 from 99, we get 15.
Fetch the next digit (6) from the dividend, attach it to 15 and continue: 156 / 21

Let's proceed to step 5:
21 can be fit into 156 7 times, resulting in a remainder of 9.
The next digit of our result is 7. 
Result so far: 4047.0
Subtracting 147 from 156 leaves us with 9.
Take the next digit (5) from the dividend and append it to 9, then repeat: 95 / 21

Step 6:
21 can be fit into 95 4 times, resulting in a remainder of 11.
The number 4 becomes the next digit in our result. 
Result so far: 40474.0
If we take 84 away from 95, we end up with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

On to step 7:
21 can be fit into 110 5 times, resulting in a remainder of 5.
The next digit of our result is 5. 
Result so far: 40474.5
The remainder is 5 after subtracting 105 from 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Let's proceed to step 8:
21 can be fit into 50 2 times, resulting in a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 40474.52
If we take 42 away from 50, we end up with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Let's proceed to step 9:
21 goes into 80 3 times with a remainder of 17.
Write down 3 as next digit of the result. 
Result so far: 40474.523
If we subtract 63 from 80, we get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Let's proceed to step 10:
170 divided by 21 is 8 with a remainder of 2.
Record the quotient 8 as the next digit in the result. 
Result so far: 40474.5238
If we take 168 away from 170, we end up with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Step 11:
The number 21 fits into 20 0 times, leaving a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 40474.5238
Subtracting 0 from 20 leaves us with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

On to step 12:
When dividing 200 by 21, we get 9 with a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 40474.523809
The remainder is 11 after subtracting 189 from 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Moving on to step 13:
When dividing 110 by 21, we get 5 with a remainder of 5.
The next digit of our result is 5. 
Result so far: 40474.5238095
Deduct 105 from 110 and we're left with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

On to step 14:
If we divide 50 by 21, we get 2 and a remainder of 8.
The next digit of our result is 2. 
Result so far: 40474.52380952
Subtract 42 from 50 to get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

After the division, we end up with 40474.52380952 and a remainder of 8e-09.