138126 divided by 13 
The aim is to understand the frequency of 13 in 138126.

Advancing 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
If we take 0 away from 1, we end up with 1.
Append the next digit (3) from the dividend to 1 and continue with: 13 / 13

Step 2:
13 goes into 13 1 times with a remainder of 0.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Deduct 13 from 13 and we're left with 0.
Grab the next digit (8) from the dividend, add it to 0, then carry on: 8 / 13

Going ahead to step 3:
The number 13 fits into 8 0 times, leaving a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 10.0
Deduct 0 from 8 and we're left with 8.
Bring next digit (1) of the dividend behind the 8 and repeat the process: 81 / 13

Moving on to step 4:
When dividing 81 by 13, we get 6 with a remainder of 3.
Write down 6 as next digit of the result. 
Result so far: 106.0
Subtract 78 from 81 to get 3.
Grab the next digit (2) from the dividend, add it to 3, then carry on: 32 / 13

Going ahead to step 5:
The number 13 fits into 32 2 times, leaving a remainder of 6.
Use 2 as the next digit of our solution. 
Result so far: 1062.0
Subtracting 26 from 32 leaves us with 6.
Include the next digit (6) from the dividend after 6, then repeat: 66 / 13

Advancing to step 6:
13 can be fit into 66 5 times, resulting in a remainder of 1.
Use 5 as the next digit of our solution. 
Result so far: 10625.0
Subtract 65 from 66 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 7:
If we divide 10 by 13, we get 0 and a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 10625.0
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.

Going ahead to step 8:
The number 13 fits into 100 7 times, leaving a remainder of 9.
Record the quotient 7 as the next digit in the result. 
Result so far: 10625.07
Subtract 91 from 100 to 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.

Let's proceed to step 9:
13 can be fit into 90 6 times, resulting in a remainder of 12.
Use 6 as the next digit of our solution. 
Result so far: 10625.076
If we take 78 away from 90, 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.

Advancing to step 10:
When dividing 120 by 13, we get 9 with a remainder of 3.
Put 9 as the next digit of the answer. 
Result so far: 10625.0769
If we take 117 away from 120, we end up 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.

Let's proceed to step 11:
When dividing 30 by 13, we get 2 with a remainder of 4.
The number 2 becomes the next digit in our result. 
Result so far: 10625.07692
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.

Moving on to step 12:
When dividing 40 by 13, we get 3 with a remainder of 1.
The number 3 becomes the next digit in our result. 
Result so far: 10625.076923
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.

Advancing to step 13:
When dividing 10 by 13, we get 0 with a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 10625.076923
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.

Moving on to step 14:
When dividing 100 by 13, we get 7 with a remainder of 9.
The number 7 becomes the next digit in our result. 
Result so far: 10625.07692307
Subtract 91 from 100 to 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.

After the division, we end up with 10625.07692307 and a remainder of 9e-09.