115998 divided by 13 
The aim is to understand the frequency of 13 in 115998.

Let's proceed to step 1:
If we divide 1 by 13, we get 0 and a remainder of 1.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 1 to get 1.
Fetch the next digit (1) from the dividend, attach it to 1 and continue: 11 / 13

Step 2:
When dividing 11 by 13, we get 0 with a remainder of 11.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 11 to get 11.
Fetch the next digit (5) from the dividend, attach it to 11 and continue: 115 / 13

On to step 3:
13 goes into 115 8 times with a remainder of 11.
Record the quotient 8 as the next digit in the result. 
Result so far: 8.0
Subtracting 104 from 115 leaves us with 11.
Bring next digit (9) of the dividend behind the 11 and repeat the process: 119 / 13

Step 4:
119 divided by 13 is 9 with a remainder of 2.
The number 9 becomes the next digit in our result. 
Result so far: 89.0
Deduct 117 from 119 and we're left with 2.
Fetch the next digit (9) from the dividend, attach it to 2 and continue: 29 / 13

Moving on to step 5:
If we divide 29 by 13, we get 2 and a remainder of 3.
Write down 2 as next digit of the result. 
Result so far: 892.0
Subtracting 26 from 29 leaves us with 3.
Append the next digit (8) from the dividend to 3 and continue with: 38 / 13

Step 6:
13 goes into 38 2 times with a remainder of 12.
Put 2 as the next digit of the answer. 
Result so far: 8922.0
Subtract 26 from 38 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Advancing to step 7:
If we divide 120 by 13, we get 9 and a remainder of 3.
Put 9 as the next digit of the answer. 
Result so far: 8922.9
Subtracting 117 from 120 leaves us 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.

Step 8:
30 divided by 13 is 2 with a remainder of 4.
Use 2 as the next digit of our solution. 
Result so far: 8922.92
Deduct 26 from 30 and we're left 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.

On to step 9:
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: 8922.923
Subtracting 39 from 40 leaves us 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.

On to step 10:
13 goes into 10 0 times with a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 8922.923
Deduct 0 from 10 and we're left 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.

Step 11:
When dividing 100 by 13, we get 7 with a remainder of 9.
Put 7 as the next digit of the answer. 
Result so far: 8922.92307
Deduct 91 from 100 and we're left with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

On to step 12:
90 divided by 13 is 6 with a remainder of 12.
The number 6 becomes the next digit in our result. 
Result so far: 8922.923076
Subtract 78 from 90 to get 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 13:
13 goes into 120 9 times with a remainder of 3.
Record the quotient 9 as the next digit in the result. 
Result so far: 8922.9230769
If we subtract 117 from 120, we get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Advancing to step 14:
The number 13 fits into 30 2 times, leaving a remainder of 4.
The number 2 becomes the next digit in our result. 
Result so far: 8922.92307692
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.

The final outcome is 8922.92307692, with a leftover of 4e-09.