We're dividing 12901885 by 518 
The aim is to understand the frequency of 518 in 12901885.

Let's proceed to step 1:
If we divide 1 by 518, we get 0 and a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 1, we get 1.
Take the next digit (2) from the dividend and append it to 1, then repeat: 12 / 518

Step 2:
12 divided by 518 is 0 with a remainder of 12.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 12, we end up with 12.
Bring next digit (9) of the dividend behind the 12 and repeat the process: 129 / 518

Moving on to step 3:
518 goes into 129 0 times with a remainder of 129.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 129, we end up with 129.
Include the next digit (0) from the dividend after 129, then repeat: 1290 / 518

Let's proceed to step 4:
1290 divided by 518 is 2 with a remainder of 254.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
Deduct 1036 from 1290 and we're left with 254.
Bring next digit (1) of the dividend behind the 254 and repeat the process: 2541 / 518

Step 5:
518 can be fit into 2541 4 times, resulting in a remainder of 469.
Write down 4 as next digit of the result. 
Result so far: 24.0
Subtracting 2072 from 2541 leaves us with 469.
Grab the next digit (8) from the dividend, add it to 469, then carry on: 4698 / 518

On to step 6:
If we divide 4698 by 518, we get 9 and a remainder of 36.
Put 9 as the next digit of the answer. 
Result so far: 249.0
The remainder is 36 after subtracting 4662 from 4698.
Take the next digit (8) from the dividend and append it to 36, then repeat: 368 / 518

Step 7:
518 can be fit into 368 0 times, resulting in a remainder of 368.
Record the quotient 0 as the next digit in the result. 
Result so far: 2490.0
If we subtract 0 from 368, we get 368.
Include the next digit (5) from the dividend after 368, then repeat: 3685 / 518

Going ahead to step 8:
3685 divided by 518 is 7 with a remainder of 59.
Put 7 as the next digit of the answer. 
Result so far: 24907.0
The remainder is 59 after subtracting 3626 from 3685.
Since there are no more digits in the dividend, we add a zero to the remainder making it 590, and continue the process.

Advancing to step 9:
If we divide 590 by 518, we get 1 and a remainder of 72.
Use 1 as the next digit of our solution. 
Result so far: 24907.1
Subtract 518 from 590 to get 72.
Since there are no more digits in the dividend, we add a zero to the remainder making it 720, and continue the process.

On to step 10:
518 goes into 720 1 times with a remainder of 202.
The number 1 becomes the next digit in our result. 
Result so far: 24907.11
Subtracting 518 from 720 leaves us with 202.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2020, and continue the process.

After the division, we end up with 24907.11 and a remainder of 0.202.