We look at the division of 635608 by 13 
The aim is to understand the frequency of 13 in 635608.

Step 1:
The number 13 fits into 6 0 times, leaving a remainder of 6.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Fetch the next digit (3) from the dividend, attach it to 6 and continue: 63 / 13

Let's proceed to step 2:
63 divided by 13 is 4 with a remainder of 11.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
The remainder is 11 after subtracting 52 from 63.
Take the next digit (5) from the dividend and append it to 11, then repeat: 115 / 13

Going ahead to step 3:
The number 13 fits into 115 8 times, leaving a remainder of 11.
The number 8 becomes the next digit in our result. 
Result so far: 48.0
Deduct 104 from 115 and we're left with 11.
Take the next digit (6) from the dividend and append it to 11, then repeat: 116 / 13

Going ahead to step 4:
116 divided by 13 is 8 with a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 488.0
If we subtract 104 from 116, we get 12.
Grab the next digit (0) from the dividend, add it to 12, then carry on: 120 / 13

Going ahead to step 5:
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: 4889.0
Deduct 117 from 120 and we're left with 3.
Fetch the next digit (8) from the dividend, attach it to 3 and continue: 38 / 13

Let's proceed to step 6:
If we divide 38 by 13, we get 2 and a remainder of 12.
Use 2 as the next digit of our solution. 
Result so far: 48892.0
If we take 26 away from 38, we end up 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 7:
13 goes into 120 9 times with a remainder of 3.
Use 9 as the next digit of our solution. 
Result so far: 48892.9
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.

On to step 8:
13 goes into 30 2 times with a remainder of 4.
Use 2 as the next digit of our solution. 
Result so far: 48892.92
The remainder is 4 after subtracting 26 from 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 9:
When dividing 40 by 13, we get 3 with a remainder of 1.
Record the quotient 3 as the next digit in the result. 
Result so far: 48892.923
Subtract 39 from 40 to 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.

On to step 10:
13 can be fit into 10 0 times, resulting in a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 48892.923
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 11:
13 can be fit into 100 7 times, resulting in a remainder of 9.
Record the quotient 7 as the next digit in the result. 
Result so far: 48892.92307
The remainder is 9 after subtracting 91 from 100.
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:
13 goes into 90 6 times with a remainder of 12.
Write down 6 as next digit of the result. 
Result so far: 48892.923076
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.

Step 13:
13 can be fit into 120 9 times, resulting in a remainder of 3.
The next digit of our result is 9. 
Result so far: 48892.9230769
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.

On to step 14:
30 divided by 13 is 2 with a remainder of 4.
The next digit of our result is 2. 
Result so far: 48892.92307692
Subtract 26 from 30 to 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.

The quotient of the division is 48892.92307692, and the remainder is 4e-09.