Let's divide 304479 by 21
The aim is to understand the frequency of 21 in 304479.

Moving on to step 1:
When dividing 3 by 21, we get 0 with a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 3, we end up with 3.
Append the next digit (0) from the dividend to 3 and continue with: 30 / 21

On to step 2:
21 can be fit into 30 1 times, resulting in a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we take 21 away from 30, we end up with 9.
Take the next digit (4) from the dividend and append it to 9, then repeat: 94 / 21

On to step 3:
If we divide 94 by 21, we get 4 and a remainder of 10.
Record the quotient 4 as the next digit in the result. 
Result so far: 14.0
Deduct 84 from 94 and we're left with 10.
Bring next digit (4) of the dividend behind the 10 and repeat the process: 104 / 21

Step 4:
When dividing 104 by 21, we get 4 with a remainder of 20.
Put 4 as the next digit of the answer. 
Result so far: 144.0
If we take 84 away from 104, we end up with 20.
Grab the next digit (7) from the dividend, add it to 20, then carry on: 207 / 21

On to step 5:
207 divided by 21 is 9 with a remainder of 18.
The next digit of our result is 9. 
Result so far: 1449.0
If we take 189 away from 207, we end up with 18.
Take the next digit (9) from the dividend and append it to 18, then repeat: 189 / 21

Going ahead to step 6:
189 divided by 21 is 9 with a remainder of 0.
Put 9 as the next digit of the answer. 
Result so far: 14499.0
Subtracting 189 from 189 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 7:
When dividing 0 by 21, we get 0 with a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 14499.0
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 8:
0 divided by 21 is 0 with a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 14499.0
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final result is 14499.0 with a remainder of 0.0.