91302581 ÷ 521 
The aim is to understand the frequency of 521 in 91302581.

Step 1:
When dividing 9 by 521, we get 0 with a remainder of 9.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 9, we end up with 9.
Fetch the next digit (1) from the dividend, attach it to 9 and continue: 91 / 521

Let's proceed to step 2:
521 can be fit into 91 0 times, resulting in a remainder of 91.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 91, we end up with 91.
Grab the next digit (3) from the dividend, add it to 91, then carry on: 913 / 521

On to step 3:
913 divided by 521 is 1 with a remainder of 392.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtracting 521 from 913 leaves us with 392.
Fetch the next digit (0) from the dividend, attach it to 392 and continue: 3920 / 521

Going ahead to step 4:
521 can be fit into 3920 7 times, resulting in a remainder of 273.
The next digit of our result is 7. 
Result so far: 17.0
Subtract 3647 from 3920 to get 273.
Fetch the next digit (2) from the dividend, attach it to 273 and continue: 2732 / 521

Advancing to step 5:
If we divide 2732 by 521, we get 5 and a remainder of 127.
The number 5 becomes the next digit in our result. 
Result so far: 175.0
Subtracting 2605 from 2732 leaves us with 127.
Grab the next digit (5) from the dividend, add it to 127, then carry on: 1275 / 521

Going ahead to step 6:
If we divide 1275 by 521, we get 2 and a remainder of 233.
Put 2 as the next digit of the answer. 
Result so far: 1752.0
Deduct 1042 from 1275 and we're left with 233.
Take the next digit (8) from the dividend and append it to 233, then repeat: 2338 / 521

Step 7:
If we divide 2338 by 521, we get 4 and a remainder of 254.
The number 4 becomes the next digit in our result. 
Result so far: 17524.0
The remainder is 254 after subtracting 2084 from 2338.
Grab the next digit (1) from the dividend, add it to 254, then carry on: 2541 / 521

Advancing to step 8:
The number 521 fits into 2541 4 times, leaving a remainder of 457.
Write down 4 as next digit of the result. 
Result so far: 175244.0
The remainder is 457 after subtracting 2084 from 2541.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4570, and continue the process.

Moving on to step 9:
521 goes into 4570 8 times with a remainder of 402.
Write down 8 as next digit of the result. 
Result so far: 175244.8
If we take 4168 away from 4570, we end up with 402.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4020, and continue the process.

Step 10:
When dividing 4020 by 521, we get 7 with a remainder of 373.
Put 7 as the next digit of the answer. 
Result so far: 175244.87
Subtracting 3647 from 4020 leaves us with 373.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3730, and continue the process.

Let's proceed to step 11:
3730 divided by 521 is 7 with a remainder of 83.
Use 7 as the next digit of our solution. 
Result so far: 175244.877
The remainder is 83 after subtracting 3647 from 3730.
Since there are no more digits in the dividend, we add a zero to the remainder making it 830, and continue the process.

The final outcome is 175244.877, with a leftover of 0.0083.