21009521 divided by 329 
The aim is to understand the frequency of 329 in 21009521.

Step 1:
329 goes into 2 0 times with a remainder of 2.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 2 leaves us with 2.
Fetch the next digit (1) from the dividend, attach it to 2 and continue: 21 / 329

Advancing to step 2:
The number 329 fits into 21 0 times, leaving a remainder of 21.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 21 after subtracting 0 from 21.
Append the next digit (0) from the dividend to 21 and continue with: 210 / 329

On to step 3:
If we divide 210 by 329, we get 0 and a remainder of 210.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 210 leaves us with 210.
Take the next digit (0) from the dividend and append it to 210, then repeat: 2100 / 329

On to step 4:
329 goes into 2100 6 times with a remainder of 126.
Use 6 as the next digit of our solution. 
Result so far: 6.0
If we subtract 1974 from 2100, we get 126.
Take the next digit (9) from the dividend and append it to 126, then repeat: 1269 / 329

Let's proceed to step 5:
When dividing 1269 by 329, we get 3 with a remainder of 282.
The next digit of our result is 3. 
Result so far: 63.0
If we subtract 987 from 1269, we get 282.
Take the next digit (5) from the dividend and append it to 282, then repeat: 2825 / 329

Going ahead to step 6:
When dividing 2825 by 329, we get 8 with a remainder of 193.
Use 8 as the next digit of our solution. 
Result so far: 638.0
The remainder is 193 after subtracting 2632 from 2825.
Grab the next digit (2) from the dividend, add it to 193, then carry on: 1932 / 329

Moving on to step 7:
329 goes into 1932 5 times with a remainder of 287.
Use 5 as the next digit of our solution. 
Result so far: 6385.0
If we subtract 1645 from 1932, we get 287.
Take the next digit (1) from the dividend and append it to 287, then repeat: 2871 / 329

On to step 8:
If we divide 2871 by 329, we get 8 and a remainder of 239.
Put 8 as the next digit of the answer. 
Result so far: 63858.0
If we subtract 2632 from 2871, we get 239.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2390, and continue the process.

On to step 9:
If we divide 2390 by 329, we get 7 and a remainder of 87.
The next digit of our result is 7. 
Result so far: 63858.7
Subtract 2303 from 2390 to get 87.
Since there are no more digits in the dividend, we add a zero to the remainder making it 870, and continue the process.

Going ahead to step 10:
When dividing 870 by 329, we get 2 with a remainder of 212.
Record the quotient 2 as the next digit in the result. 
Result so far: 63858.72
If we take 658 away from 870, we end up with 212.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2120, and continue the process.

Going ahead to step 11:
The number 329 fits into 2120 6 times, leaving a remainder of 146.
Put 6 as the next digit of the answer. 
Result so far: 63858.726
Deduct 1974 from 2120 and we're left with 146.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1460, and continue the process.

Moving on to step 12:
1460 divided by 329 is 4 with a remainder of 144.
Write down 4 as next digit of the result. 
Result so far: 63858.7264
If we subtract 1316 from 1460, we get 144.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1440, and continue the process.

On to step 13:
329 can be fit into 1440 4 times, resulting in a remainder of 124.
Write down 4 as next digit of the result. 
Result so far: 63858.72644
Subtracting 1316 from 1440 leaves us with 124.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1240, and continue the process.

After the division, we end up with 63858.72644 and a remainder of 0.000124.