We look at the division of 43251521 by 499 
The aim is to understand the frequency of 499 in 43251521.

On to step 1:
499 can be fit into 4 0 times, resulting in a remainder of 4.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 4 after subtracting 0 from 4.
Append the next digit (3) from the dividend to 4 and continue with: 43 / 499

On to step 2:
The number 499 fits into 43 0 times, leaving a remainder of 43.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 43, we get 43.
Bring next digit (2) of the dividend behind the 43 and repeat the process: 432 / 499

Moving on to step 3:
If we divide 432 by 499, we get 0 and a remainder of 432.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 432 to get 432.
Grab the next digit (5) from the dividend, add it to 432, then carry on: 4325 / 499

Let's proceed to step 4:
When dividing 4325 by 499, we get 8 with a remainder of 333.
Put 8 as the next digit of the answer. 
Result so far: 8.0
The remainder is 333 after subtracting 3992 from 4325.
Bring next digit (1) of the dividend behind the 333 and repeat the process: 3331 / 499

On to step 5:
499 can be fit into 3331 6 times, resulting in a remainder of 337.
The number 6 becomes the next digit in our result. 
Result so far: 86.0
Deduct 2994 from 3331 and we're left with 337.
Grab the next digit (5) from the dividend, add it to 337, then carry on: 3375 / 499

Moving on to step 6:
3375 divided by 499 is 6 with a remainder of 381.
Write down 6 as next digit of the result. 
Result so far: 866.0
Subtract 2994 from 3375 to get 381.
Fetch the next digit (2) from the dividend, attach it to 381 and continue: 3812 / 499

On to step 7:
If we divide 3812 by 499, we get 7 and a remainder of 319.
Use 7 as the next digit of our solution. 
Result so far: 8667.0
If we subtract 3493 from 3812, we get 319.
Grab the next digit (1) from the dividend, add it to 319, then carry on: 3191 / 499

Advancing to step 8:
499 can be fit into 3191 6 times, resulting in a remainder of 197.
The next digit of our result is 6. 
Result so far: 86676.0
Subtracting 2994 from 3191 leaves us with 197.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1970, and continue the process.

Advancing to step 9:
When dividing 1970 by 499, we get 3 with a remainder of 473.
Record the quotient 3 as the next digit in the result. 
Result so far: 86676.3
The remainder is 473 after subtracting 1497 from 1970.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4730, and continue the process.

Going ahead to step 10:
499 goes into 4730 9 times with a remainder of 239.
The next digit of our result is 9. 
Result so far: 86676.39
Deduct 4491 from 4730 and we're left with 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 11:
The number 499 fits into 2390 4 times, leaving a remainder of 394.
Put 4 as the next digit of the answer. 
Result so far: 86676.394
If we subtract 1996 from 2390, we get 394.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3940, and continue the process.

Moving on to step 12:
499 goes into 3940 7 times with a remainder of 447.
Use 7 as the next digit of our solution. 
Result so far: 86676.3947
Deduct 3493 from 3940 and we're left with 447.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4470, and continue the process.

On to step 13:
499 goes into 4470 8 times with a remainder of 478.
The next digit of our result is 8. 
Result so far: 86676.39478
Deduct 3992 from 4470 and we're left with 478.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4780, and continue the process.

Moving on to step 14:
499 can be fit into 4780 9 times, resulting in a remainder of 289.
The number 9 becomes the next digit in our result. 
Result so far: 86676.394789
If we take 4491 away from 4780, we end up with 289.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2890, and continue the process.

Going ahead to step 15:
The number 499 fits into 2890 5 times, leaving a remainder of 395.
The number 5 becomes the next digit in our result. 
Result so far: 86676.3947895
Deduct 2495 from 2890 and we're left with 395.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3950, and continue the process.

Step 16:
When dividing 3950 by 499, we get 7 with a remainder of 457.
Use 7 as the next digit of our solution. 
Result so far: 86676.39478957
If we take 3493 away from 3950, we end up with 457.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4570, and continue the process.

The final outcome is 86676.39478957, with a leftover of 4.57e-07.