We look at the division of 66571 by 86 
The aim is to understand the frequency of 86 in 66571.

Going ahead to step 1:
The number 86 fits into 6 0 times, leaving a remainder of 6.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Grab the next digit (6) from the dividend, add it to 6, then carry on: 66 / 86

Let's proceed to step 2:
When dividing 66 by 86, we get 0 with a remainder of 66.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 66, we end up with 66.
Append the next digit (5) from the dividend to 66 and continue with: 665 / 86

Going ahead to step 3:
The number 86 fits into 665 7 times, leaving a remainder of 63.
Use 7 as the next digit of our solution. 
Result so far: 7.0
Subtract 602 from 665 to get 63.
Include the next digit (7) from the dividend after 63, then repeat: 637 / 86

Step 4:
If we divide 637 by 86, we get 7 and a remainder of 35.
Use 7 as the next digit of our solution. 
Result so far: 77.0
Deduct 602 from 637 and we're left with 35.
Append the next digit (1) from the dividend to 35 and continue with: 351 / 86

Let's proceed to step 5:
When dividing 351 by 86, we get 4 with a remainder of 7.
Put 4 as the next digit of the answer. 
Result so far: 774.0
If we take 344 away from 351, we end up with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Advancing to step 6:
When dividing 70 by 86, we get 0 with a remainder of 70.
Put 0 as the next digit of the answer. 
Result so far: 774.0
The remainder is 70 after subtracting 0 from 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

On to step 7:
The number 86 fits into 700 8 times, leaving a remainder of 12.
Put 8 as the next digit of the answer. 
Result so far: 774.08
Subtract 688 from 700 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Advancing to step 8:
The number 86 fits into 120 1 times, leaving a remainder of 34.
Record the quotient 1 as the next digit in the result. 
Result so far: 774.081
Deduct 86 from 120 and we're left with 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

Let's proceed to step 9:
When dividing 340 by 86, we get 3 with a remainder of 82.
Put 3 as the next digit of the answer. 
Result so far: 774.0813
Deduct 258 from 340 and we're left with 82.
Since there are no more digits in the dividend, we add a zero to the remainder making it 820, and continue the process.

On to step 10:
When dividing 820 by 86, we get 9 with a remainder of 46.
The next digit of our result is 9. 
Result so far: 774.08139
If we take 774 away from 820, we end up with 46.
Since there are no more digits in the dividend, we add a zero to the remainder making it 460, and continue the process.

Step 11:
When dividing 460 by 86, we get 5 with a remainder of 30.
Record the quotient 5 as the next digit in the result. 
Result so far: 774.081395
Deduct 430 from 460 and we're left with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Let's proceed to step 12:
86 goes into 300 3 times with a remainder of 42.
Record the quotient 3 as the next digit in the result. 
Result so far: 774.0813953
The remainder is 42 after subtracting 258 from 300.
Since there are no more digits in the dividend, we add a zero to the remainder making it 420, and continue the process.

Let's proceed to step 13:
The number 86 fits into 420 4 times, leaving a remainder of 76.
The number 4 becomes the next digit in our result. 
Result so far: 774.08139534
Subtracting 344 from 420 leaves us with 76.
Since there are no more digits in the dividend, we add a zero to the remainder making it 760, and continue the process.

Our division results in 774.08139534 with a remaining 7.6e-08.