We look at the division of 835878 by 13 
The aim is to understand the frequency of 13 in 835878.

On to step 1:
When dividing 8 by 13, we get 0 with a remainder of 8.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 8, we end up with 8.
Bring next digit (3) of the dividend behind the 8 and repeat the process: 83 / 13

Step 2:
If we divide 83 by 13, we get 6 and a remainder of 5.
The number 6 becomes the next digit in our result. 
Result so far: 6.0
Subtracting 78 from 83 leaves us with 5.
Include the next digit (5) from the dividend after 5, then repeat: 55 / 13

Moving on to step 3:
55 divided by 13 is 4 with a remainder of 3.
Use 4 as the next digit of our solution. 
Result so far: 64.0
The remainder is 3 after subtracting 52 from 55.
Fetch the next digit (8) from the dividend, attach it to 3 and continue: 38 / 13

Advancing to step 4:
If we divide 38 by 13, we get 2 and a remainder of 12.
Record the quotient 2 as the next digit in the result. 
Result so far: 642.0
Deduct 26 from 38 and we're left with 12.
Grab the next digit (7) from the dividend, add it to 12, then carry on: 127 / 13

On to step 5:
When dividing 127 by 13, we get 9 with a remainder of 10.
The number 9 becomes the next digit in our result. 
Result so far: 6429.0
If we subtract 117 from 127, we get 10.
Include the next digit (8) from the dividend after 10, then repeat: 108 / 13

Moving on to step 6:
13 can be fit into 108 8 times, resulting in a remainder of 4.
Put 8 as the next digit of the answer. 
Result so far: 64298.0
If we subtract 104 from 108, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 7:
40 divided by 13 is 3 with a remainder of 1.
Record the quotient 3 as the next digit in the result. 
Result so far: 64298.3
If we take 39 away from 40, 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.

Going ahead to step 8:
13 goes into 10 0 times with a remainder of 10.
The next digit of our result is 0. 
Result so far: 64298.3
If we take 0 away from 10, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 9:
13 can be fit into 100 7 times, resulting in a remainder of 9.
The number 7 becomes the next digit in our result. 
Result so far: 64298.307
If we subtract 91 from 100, we get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Moving on to step 10:
If we divide 90 by 13, we get 6 and a remainder of 12.
The number 6 becomes the next digit in our result. 
Result so far: 64298.3076
Deduct 78 from 90 and we're left with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

On to step 11:
When dividing 120 by 13, we get 9 with a remainder of 3.
Record the quotient 9 as the next digit in the result. 
Result so far: 64298.30769
Deduct 117 from 120 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 12:
30 divided by 13 is 2 with a remainder of 4.
The number 2 becomes the next digit in our result. 
Result so far: 64298.307692
If we take 26 away from 30, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 13:
40 divided by 13 is 3 with a remainder of 1.
Put 3 as the next digit of the answer. 
Result so far: 64298.3076923
If we subtract 39 from 40, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Advancing to step 14:
10 divided by 13 is 0 with a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 64298.3076923
If we subtract 0 from 10, we 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.

The final outcome is 64298.3076923, with a leftover of 1e-08.