We look at the division of 87352303 by 866 
The aim is to understand the frequency of 866 in 87352303.

Advancing to step 1:
8 divided by 866 is 0 with a remainder of 8.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 8 after subtracting 0 from 8.
Take the next digit (7) from the dividend and append it to 8, then repeat: 87 / 866

Moving on to step 2:
866 can be fit into 87 0 times, resulting in a remainder of 87.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 87, we end up with 87.
Include the next digit (3) from the dividend after 87, then repeat: 873 / 866

Step 3:
The number 866 fits into 873 1 times, leaving a remainder of 7.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Subtracting 866 from 873 leaves us with 7.
Grab the next digit (5) from the dividend, add it to 7, then carry on: 75 / 866

Moving on to step 4:
866 goes into 75 0 times with a remainder of 75.
The next digit of our result is 0. 
Result so far: 10.0
Deduct 0 from 75 and we're left with 75.
Append the next digit (2) from the dividend to 75 and continue with: 752 / 866

Advancing to step 5:
The number 866 fits into 752 0 times, leaving a remainder of 752.
Record the quotient 0 as the next digit in the result. 
Result so far: 100.0
The remainder is 752 after subtracting 0 from 752.
Append the next digit (3) from the dividend to 752 and continue with: 7523 / 866

On to step 6:
If we divide 7523 by 866, we get 8 and a remainder of 595.
Put 8 as the next digit of the answer. 
Result so far: 1008.0
If we subtract 6928 from 7523, we get 595.
Bring next digit (0) of the dividend behind the 595 and repeat the process: 5950 / 866

Step 7:
866 goes into 5950 6 times with a remainder of 754.
The number 6 becomes the next digit in our result. 
Result so far: 10086.0
Subtract 5196 from 5950 to get 754.
Fetch the next digit (3) from the dividend, attach it to 754 and continue: 7543 / 866

Step 8:
866 can be fit into 7543 8 times, resulting in a remainder of 615.
Write down 8 as next digit of the result. 
Result so far: 100868.0
If we take 6928 away from 7543, we end up with 615.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6150, and continue the process.

Advancing to step 9:
The number 866 fits into 6150 7 times, leaving a remainder of 88.
The number 7 becomes the next digit in our result. 
Result so far: 100868.7
Subtracting 6062 from 6150 leaves us with 88.
Since there are no more digits in the dividend, we add a zero to the remainder making it 880, and continue the process.

Moving on to step 10:
When dividing 880 by 866, we get 1 with a remainder of 14.
Use 1 as the next digit of our solution. 
Result so far: 100868.71
Subtracting 866 from 880 leaves us with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Step 11:
The number 866 fits into 140 0 times, leaving a remainder of 140.
The number 0 becomes the next digit in our result. 
Result so far: 100868.71
Deduct 0 from 140 and we're left with 140.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1400, and continue the process.

Going ahead to step 12:
When dividing 1400 by 866, we get 1 with a remainder of 534.
The number 1 becomes the next digit in our result. 
Result so far: 100868.7101
Deduct 866 from 1400 and we're left with 534.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5340, and continue the process.

Advancing to step 13:
5340 divided by 866 is 6 with a remainder of 144.
Record the quotient 6 as the next digit in the result. 
Result so far: 100868.71016
Subtracting 5196 from 5340 leaves us with 144.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1440, and continue the process.

On to step 14:
866 goes into 1440 1 times with a remainder of 574.
Record the quotient 1 as the next digit in the result. 
Result so far: 100868.710161
Deduct 866 from 1440 and we're left with 574.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5740, and continue the process.

Step 15:
866 goes into 5740 6 times with a remainder of 544.
The number 6 becomes the next digit in our result. 
Result so far: 100868.7101616
Deduct 5196 from 5740 and we're left with 544.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5440, and continue the process.

Moving on to step 16:
5440 divided by 866 is 6 with a remainder of 244.
The number 6 becomes the next digit in our result. 
Result so far: 100868.71016166
If we subtract 5196 from 5440, we get 244.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2440, and continue the process.

The final outcome is 100868.71016166, with a leftover of 2.44e-07.