We look at the division of 645591 by 85 
The aim is to understand the frequency of 85 in 645591.

Moving on to step 1:
If we divide 6 by 85, we get 0 and 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.
Bring next digit (4) of the dividend behind the 6 and repeat the process: 64 / 85

Let's proceed to step 2:
If we divide 64 by 85, we get 0 and a remainder of 64.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 64, we end up with 64.
Append the next digit (5) from the dividend to 64 and continue with: 645 / 85

Going ahead to step 3:
The number 85 fits into 645 7 times, leaving a remainder of 50.
Record the quotient 7 as the next digit in the result. 
Result so far: 7.0
If we take 595 away from 645, we end up with 50.
Bring next digit (5) of the dividend behind the 50 and repeat the process: 505 / 85

On to step 4:
85 goes into 505 5 times with a remainder of 80.
The number 5 becomes the next digit in our result. 
Result so far: 75.0
If we take 425 away from 505, we end up with 80.
Append the next digit (9) from the dividend to 80 and continue with: 809 / 85

Going ahead to step 5:
809 divided by 85 is 9 with a remainder of 44.
Write down 9 as next digit of the result. 
Result so far: 759.0
Subtracting 765 from 809 leaves us with 44.
Fetch the next digit (1) from the dividend, attach it to 44 and continue: 441 / 85

Moving on to step 6:
The number 85 fits into 441 5 times, leaving a remainder of 16.
Put 5 as the next digit of the answer. 
Result so far: 7595.0
Subtracting 425 from 441 leaves us with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Advancing to step 7:
85 can be fit into 160 1 times, resulting in a remainder of 75.
Use 1 as the next digit of our solution. 
Result so far: 7595.1
Deduct 85 from 160 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.

Going ahead to step 8:
85 goes into 750 8 times with a remainder of 70.
Put 8 as the next digit of the answer. 
Result so far: 7595.18
Deduct 680 from 750 and we're left with 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Advancing to step 9:
When dividing 700 by 85, we get 8 with a remainder of 20.
The number 8 becomes the next digit in our result. 
Result so far: 7595.188
If we take 680 away from 700, we end up with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

In conclusion, the division gives 7595.188 with a balance of 0.002.