We look at the division of 866406 by 85 
The aim is to understand the frequency of 85 in 866406.

Going ahead to step 1:
8 divided by 85 is 0 with a remainder of 8.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 8, we end up with 8.
Append the next digit (6) from the dividend to 8 and continue with: 86 / 85

Going ahead to step 2:
86 divided by 85 is 1 with a remainder of 1.
Put 1 as the next digit of the answer. 
Result so far: 1.0
If we subtract 85 from 86, we get 1.
Fetch the next digit (6) from the dividend, attach it to 1 and continue: 16 / 85

Advancing to step 3:
16 divided by 85 is 0 with a remainder of 16.
Put 0 as the next digit of the answer. 
Result so far: 10.0
If we subtract 0 from 16, we get 16.
Take the next digit (4) from the dividend and append it to 16, then repeat: 164 / 85

On to step 4:
The number 85 fits into 164 1 times, leaving a remainder of 79.
The next digit of our result is 1. 
Result so far: 101.0
If we take 85 away from 164, we end up with 79.
Grab the next digit (0) from the dividend, add it to 79, then carry on: 790 / 85

Step 5:
When dividing 790 by 85, we get 9 with a remainder of 25.
Write down 9 as next digit of the result. 
Result so far: 1019.0
The remainder is 25 after subtracting 765 from 790.
Include the next digit (6) from the dividend after 25, then repeat: 256 / 85

Advancing to step 6:
The number 85 fits into 256 3 times, leaving a remainder of 1.
Record the quotient 3 as the next digit in the result. 
Result so far: 10193.0
If we take 255 away from 256, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 7:
When dividing 10 by 85, we get 0 with a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 10193.0
Subtract 0 from 10 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

On to step 8:
100 divided by 85 is 1 with a remainder of 15.
Write down 1 as next digit of the result. 
Result so far: 10193.01
If we subtract 85 from 100, we get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Going ahead to step 9:
If we divide 150 by 85, we get 1 and a remainder of 65.
Write down 1 as next digit of the result. 
Result so far: 10193.011
If we take 85 away from 150, we end up with 65.
Since there are no more digits in the dividend, we add a zero to the remainder making it 650, and continue the process.

The final result is 10193.011 with a remainder of 0.0065.