We look at the division of 865599 by 13 
The aim is to understand the frequency of 13 in 865599.

On to step 1:
13 goes into 8 0 times with a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Take the next digit (6) from the dividend and append it to 8, then repeat: 86 / 13

Going ahead to step 2:
The number 13 fits into 86 6 times, leaving a remainder of 8.
The number 6 becomes the next digit in our result. 
Result so far: 6.0
If we take 78 away from 86, we end up with 8.
Grab the next digit (5) from the dividend, add it to 8, then carry on: 85 / 13

On to step 3:
13 can be fit into 85 6 times, resulting in a remainder of 7.
Use 6 as the next digit of our solution. 
Result so far: 66.0
If we take 78 away from 85, we end up with 7.
Grab the next digit (5) from the dividend, add it to 7, then carry on: 75 / 13

On to step 4:
13 can be fit into 75 5 times, resulting in a remainder of 10.
Record the quotient 5 as the next digit in the result. 
Result so far: 665.0
Subtracting 65 from 75 leaves us with 10.
Bring next digit (9) of the dividend behind the 10 and repeat the process: 109 / 13

Moving on to step 5:
If we divide 109 by 13, we get 8 and a remainder of 5.
The next digit of our result is 8. 
Result so far: 6658.0
Subtracting 104 from 109 leaves us with 5.
Bring next digit (9) of the dividend behind the 5 and repeat the process: 59 / 13

Moving on to step 6:
The number 13 fits into 59 4 times, leaving a remainder of 7.
Use 4 as the next digit of our solution. 
Result so far: 66584.0
Subtracting 52 from 59 leaves us 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.

Moving on to step 7:
13 can be fit into 70 5 times, resulting in a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 66584.5
Deduct 65 from 70 and we're left with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Going ahead to step 8:
50 divided by 13 is 3 with a remainder of 11.
Put 3 as the next digit of the answer. 
Result so far: 66584.53
If we take 39 away from 50, we end up with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

On to step 9:
If we divide 110 by 13, we get 8 and a remainder of 6.
Use 8 as the next digit of our solution. 
Result so far: 66584.538
Subtract 104 from 110 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 10:
When dividing 60 by 13, we get 4 with a remainder of 8.
The next digit of our result is 4. 
Result so far: 66584.5384
If we subtract 52 from 60, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

On to step 11:
13 can be fit into 80 6 times, resulting in a remainder of 2.
Use 6 as the next digit of our solution. 
Result so far: 66584.53846
If we take 78 away from 80, we end up with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Let's proceed to step 12:
If we divide 20 by 13, we get 1 and a remainder of 7.
Write down 1 as next digit of the result. 
Result so far: 66584.538461
Subtract 13 from 20 to get 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Going ahead to step 13:
The number 13 fits into 70 5 times, leaving a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 66584.5384615
If we subtract 65 from 70, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Step 14:
If we divide 50 by 13, we get 3 and a remainder of 11.
Put 3 as the next digit of the answer. 
Result so far: 66584.53846153
Deduct 39 from 50 and we're left with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

The quotient of the division is 66584.53846153, and the remainder is 1.1e-08.