494564 ÷ 21 
The aim is to understand the frequency of 21 in 494564.

On to step 1:
The number 21 fits into 4 0 times, leaving a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 4 to get 4.
Append the next digit (9) from the dividend to 4 and continue with: 49 / 21

Step 2:
When dividing 49 by 21, we get 2 with a remainder of 7.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
If we subtract 42 from 49, we get 7.
Include the next digit (4) from the dividend after 7, then repeat: 74 / 21

Step 3:
21 can be fit into 74 3 times, resulting in a remainder of 11.
Use 3 as the next digit of our solution. 
Result so far: 23.0
Deduct 63 from 74 and we're left with 11.
Append the next digit (5) from the dividend to 11 and continue with: 115 / 21

On to step 4:
The number 21 fits into 115 5 times, leaving a remainder of 10.
Write down 5 as next digit of the result. 
Result so far: 235.0
Deduct 105 from 115 and we're left with 10.
Fetch the next digit (6) from the dividend, attach it to 10 and continue: 106 / 21

Moving on to step 5:
When dividing 106 by 21, we get 5 with a remainder of 1.
The next digit of our result is 5. 
Result so far: 2355.0
If we subtract 105 from 106, we get 1.
Include the next digit (4) from the dividend after 1, then repeat: 14 / 21

Step 6:
When dividing 14 by 21, we get 0 with a remainder of 14.
The number 0 becomes the next digit in our result. 
Result so far: 23550.0
Subtracting 0 from 14 leaves us with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Advancing to step 7:
The number 21 fits into 140 6 times, leaving a remainder of 14.
Put 6 as the next digit of the answer. 
Result so far: 23550.6
Subtract 126 from 140 to get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Going ahead to step 8:
140 divided by 21 is 6 with a remainder of 14.
Record the quotient 6 as the next digit in the result. 
Result so far: 23550.66
Subtract 126 from 140 to get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Our division results in 23550.66 with a remaining 0.014.