496666 divided by 21 
The aim is to understand the frequency of 21 in 496666.

Moving on to step 1:
If we divide 4 by 21, we get 0 and a remainder of 4.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 4 leaves us with 4.
Include the next digit (9) from the dividend after 4, then repeat: 49 / 21

Step 2:
When dividing 49 by 21, we get 2 with a remainder of 7.
Write down 2 as next digit of the result. 
Result so far: 2.0
Subtracting 42 from 49 leaves us with 7.
Fetch the next digit (6) from the dividend, attach it to 7 and continue: 76 / 21

Step 3:
If we divide 76 by 21, we get 3 and a remainder of 13.
Use 3 as the next digit of our solution. 
Result so far: 23.0
Deduct 63 from 76 and we're left with 13.
Include the next digit (6) from the dividend after 13, then repeat: 136 / 21

Let's proceed to step 4:
When dividing 136 by 21, we get 6 with a remainder of 10.
The next digit of our result is 6. 
Result so far: 236.0
If we take 126 away from 136, we end up with 10.
Fetch the next digit (6) from the dividend, attach it to 10 and continue: 106 / 21

Let's proceed to step 5:
21 can be fit into 106 5 times, resulting in a remainder of 1.
Record the quotient 5 as the next digit in the result. 
Result so far: 2365.0
If we take 105 away from 106, we end up with 1.
Include the next digit (6) from the dividend after 1, then repeat: 16 / 21

Advancing to step 6:
16 divided by 21 is 0 with a remainder of 16.
Write down 0 as next digit of the result. 
Result so far: 23650.0
If we subtract 0 from 16, 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.

Moving on to step 7:
21 can be fit into 160 7 times, resulting in a remainder of 13.
Put 7 as the next digit of the answer. 
Result so far: 23650.7
Deduct 147 from 160 and we're left 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.

Let's proceed to step 8:
21 goes into 130 6 times with a remainder of 4.
The number 6 becomes the next digit in our result. 
Result so far: 23650.76
Subtract 126 from 130 to get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Advancing to step 9:
The number 21 fits into 40 1 times, leaving a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 23650.761
If we subtract 21 from 40, we get 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 10:
The number 21 fits into 190 9 times, leaving a remainder of 1.
The next digit of our result is 9. 
Result so far: 23650.7619
Subtracting 189 from 190 leaves us 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.

Let's proceed to step 11:
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: 23650.7619
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 12:
When dividing 100 by 21, we get 4 with a remainder of 16.
Put 4 as the next digit of the answer. 
Result so far: 23650.761904
Subtracting 84 from 100 leaves us 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 13:
21 can be fit into 160 7 times, resulting in a remainder of 13.
Put 7 as the next digit of the answer. 
Result so far: 23650.7619047
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.

Moving on to step 14:
If we divide 130 by 21, we get 6 and a remainder of 4.
Put 6 as the next digit of the answer. 
Result so far: 23650.76190476
Subtracting 126 from 130 leaves us 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.

The final outcome is 23650.76190476, with a leftover of 4e-09.