Let's divide 66813515 by 531
The aim is to understand the frequency of 531 in 66813515.

Going ahead to step 1:
When dividing 6 by 531, we get 0 with a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Include the next digit (6) from the dividend after 6, then repeat: 66 / 531

Going ahead to step 2:
The number 531 fits into 66 0 times, leaving a remainder of 66.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 66 and we're left with 66.
Take the next digit (8) from the dividend and append it to 66, then repeat: 668 / 531

Moving on to step 3:
If we divide 668 by 531, we get 1 and a remainder of 137.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtract 531 from 668 to get 137.
Bring next digit (1) of the dividend behind the 137 and repeat the process: 1371 / 531

On to step 4:
The number 531 fits into 1371 2 times, leaving a remainder of 309.
Use 2 as the next digit of our solution. 
Result so far: 12.0
If we subtract 1062 from 1371, we get 309.
Bring next digit (3) of the dividend behind the 309 and repeat the process: 3093 / 531

Let's proceed to step 5:
531 can be fit into 3093 5 times, resulting in a remainder of 438.
The next digit of our result is 5. 
Result so far: 125.0
If we subtract 2655 from 3093, we get 438.
Append the next digit (5) from the dividend to 438 and continue with: 4385 / 531

Moving on to step 6:
4385 divided by 531 is 8 with a remainder of 137.
Write down 8 as next digit of the result. 
Result so far: 1258.0
If we subtract 4248 from 4385, we get 137.
Append the next digit (1) from the dividend to 137 and continue with: 1371 / 531

Step 7:
The number 531 fits into 1371 2 times, leaving a remainder of 309.
Put 2 as the next digit of the answer. 
Result so far: 12582.0
The remainder is 309 after subtracting 1062 from 1371.
Grab the next digit (5) from the dividend, add it to 309, then carry on: 3095 / 531

Step 8:
When dividing 3095 by 531, we get 5 with a remainder of 440.
Write down 5 as next digit of the result. 
Result so far: 125825.0
If we take 2655 away from 3095, we end up with 440.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4400, and continue the process.

Let's proceed to step 9:
531 goes into 4400 8 times with a remainder of 152.
Record the quotient 8 as the next digit in the result. 
Result so far: 125825.8
Subtracting 4248 from 4400 leaves us with 152.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1520, and continue the process.

On to step 10:
1520 divided by 531 is 2 with a remainder of 458.
Use 2 as the next digit of our solution. 
Result so far: 125825.82
The remainder is 458 after subtracting 1062 from 1520.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4580, and continue the process.

Step 11:
4580 divided by 531 is 8 with a remainder of 332.
The number 8 becomes the next digit in our result. 
Result so far: 125825.828
If we take 4248 away from 4580, we end up with 332.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3320, and continue the process.

Step 12:
If we divide 3320 by 531, we get 6 and a remainder of 134.
The next digit of our result is 6. 
Result so far: 125825.8286
If we subtract 3186 from 3320, we get 134.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1340, and continue the process.

Advancing to step 13:
1340 divided by 531 is 2 with a remainder of 278.
Use 2 as the next digit of our solution. 
Result so far: 125825.82862
Subtract 1062 from 1340 to get 278.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2780, and continue the process.

Advancing to step 14:
2780 divided by 531 is 5 with a remainder of 125.
The number 5 becomes the next digit in our result. 
Result so far: 125825.828625
If we take 2655 away from 2780, we end up with 125.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1250, and continue the process.

On to step 15:
1250 divided by 531 is 2 with a remainder of 188.
Put 2 as the next digit of the answer. 
Result so far: 125825.8286252
If we take 1062 away from 1250, we end up with 188.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1880, and continue the process.

Let's proceed to step 16:
If we divide 1880 by 531, we get 3 and a remainder of 287.
The next digit of our result is 3. 
Result so far: 125825.82862523
If we take 1593 away from 1880, we end up with 287.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2870, and continue the process.

The final result is 125825.82862523 with a remainder of 2.87e-07.