We look at the division of 81266217 by 525 
The aim is to understand the frequency of 525 in 81266217.

Going ahead to step 1:
The number 525 fits into 8 0 times, leaving a remainder of 8.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Include the next digit (1) from the dividend after 8, then repeat: 81 / 525

Going ahead to step 2:
If we divide 81 by 525, we get 0 and a remainder of 81.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 81 after subtracting 0 from 81.
Include the next digit (2) from the dividend after 81, then repeat: 812 / 525

Let's proceed to step 3:
If we divide 812 by 525, we get 1 and a remainder of 287.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
Subtract 525 from 812 to get 287.
Fetch the next digit (6) from the dividend, attach it to 287 and continue: 2876 / 525

Step 4:
2876 divided by 525 is 5 with a remainder of 251.
Put 5 as the next digit of the answer. 
Result so far: 15.0
Subtracting 2625 from 2876 leaves us with 251.
Fetch the next digit (6) from the dividend, attach it to 251 and continue: 2516 / 525

Moving on to step 5:
If we divide 2516 by 525, we get 4 and a remainder of 416.
The next digit of our result is 4. 
Result so far: 154.0
Deduct 2100 from 2516 and we're left with 416.
Grab the next digit (2) from the dividend, add it to 416, then carry on: 4162 / 525

Step 6:
When dividing 4162 by 525, we get 7 with a remainder of 487.
Put 7 as the next digit of the answer. 
Result so far: 1547.0
Deduct 3675 from 4162 and we're left with 487.
Bring next digit (1) of the dividend behind the 487 and repeat the process: 4871 / 525

Going ahead to step 7:
The number 525 fits into 4871 9 times, leaving a remainder of 146.
Use 9 as the next digit of our solution. 
Result so far: 15479.0
If we subtract 4725 from 4871, we get 146.
Take the next digit (7) from the dividend and append it to 146, then repeat: 1467 / 525

Advancing to step 8:
1467 divided by 525 is 2 with a remainder of 417.
The number 2 becomes the next digit in our result. 
Result so far: 154792.0
Subtract 1050 from 1467 to get 417.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4170, and continue the process.

Let's proceed to step 9:
525 can be fit into 4170 7 times, resulting in a remainder of 495.
Use 7 as the next digit of our solution. 
Result so far: 154792.7
The remainder is 495 after subtracting 3675 from 4170.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4950, and continue the process.

Step 10:
The number 525 fits into 4950 9 times, leaving a remainder of 225.
The number 9 becomes the next digit in our result. 
Result so far: 154792.79
The remainder is 225 after subtracting 4725 from 4950.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2250, and continue the process.

On to step 11:
525 can be fit into 2250 4 times, resulting in a remainder of 150.
The next digit of our result is 4. 
Result so far: 154792.794
Subtract 2100 from 2250 to get 150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1500, and continue the process.

Advancing to step 12:
525 can be fit into 1500 2 times, resulting in a remainder of 450.
Record the quotient 2 as the next digit in the result. 
Result so far: 154792.7942
Subtracting 1050 from 1500 leaves us with 450.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4500, and continue the process.

Going ahead to step 13:
525 goes into 4500 8 times with a remainder of 300.
Put 8 as the next digit of the answer. 
Result so far: 154792.79428
The remainder is 300 after subtracting 4200 from 4500.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3000, and continue the process.

Advancing to step 14:
525 can be fit into 3000 5 times, resulting in a remainder of 375.
Write down 5 as next digit of the result. 
Result so far: 154792.794285
Deduct 2625 from 3000 and we're left with 375.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3750, and continue the process.

Advancing to step 15:
If we divide 3750 by 525, we get 7 and a remainder of 75.
Put 7 as the next digit of the answer. 
Result so far: 154792.7942857
Deduct 3675 from 3750 and we're left with 75.
Since there are no more digits in the dividend, we add a zero to the remainder making it 750, and continue the process.

Moving on to step 16:
750 divided by 525 is 1 with a remainder of 225.
The next digit of our result is 1. 
Result so far: 154792.79428571
If we subtract 525 from 750, we get 225.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2250, and continue the process.

The final result is 154792.79428571 with a remainder of 2.25e-07.