We look at the division of 51804475 by 13 
The aim is to understand the frequency of 13 in 51804475.

Step 1:
13 can be fit into 5 0 times, resulting in a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 5 leaves us with 5.
Append the next digit (1) from the dividend to 5 and continue with: 51 / 13

Moving on to step 2:
13 can be fit into 51 3 times, resulting in a remainder of 12.
Put 3 as the next digit of the answer. 
Result so far: 3.0
The remainder is 12 after subtracting 39 from 51.
Include the next digit (8) from the dividend after 12, then repeat: 128 / 13

Step 3:
13 can be fit into 128 9 times, resulting in a remainder of 11.
Put 9 as the next digit of the answer. 
Result so far: 39.0
If we subtract 117 from 128, we get 11.
Include the next digit (0) from the dividend after 11, then repeat: 110 / 13

Advancing to step 4:
If we divide 110 by 13, we get 8 and a remainder of 6.
Put 8 as the next digit of the answer. 
Result so far: 398.0
Subtract 104 from 110 to get 6.
Include the next digit (4) from the dividend after 6, then repeat: 64 / 13

On to step 5:
64 divided by 13 is 4 with a remainder of 12.
Record the quotient 4 as the next digit in the result. 
Result so far: 3984.0
If we take 52 away from 64, we end up with 12.
Include the next digit (4) from the dividend after 12, then repeat: 124 / 13

Let's proceed to step 6:
If we divide 124 by 13, we get 9 and a remainder of 7.
The next digit of our result is 9. 
Result so far: 39849.0
The remainder is 7 after subtracting 117 from 124.
Append the next digit (7) from the dividend to 7 and continue with: 77 / 13

Moving on to step 7:
When dividing 77 by 13, we get 5 with a remainder of 12.
Write down 5 as next digit of the result. 
Result so far: 398495.0
Subtracting 65 from 77 leaves us with 12.
Grab the next digit (5) from the dividend, add it to 12, then carry on: 125 / 13

Going ahead to step 8:
13 goes into 125 9 times with a remainder of 8.
Put 9 as the next digit of the answer. 
Result so far: 3984959.0
If we subtract 117 from 125, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Let's proceed to step 9:
If we divide 80 by 13, we get 6 and a remainder of 2.
Use 6 as the next digit of our solution. 
Result so far: 3984959.6
If we take 78 away from 80, we end up with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Step 10:
If we divide 20 by 13, we get 1 and a remainder of 7.
Write down 1 as next digit of the result. 
Result so far: 3984959.61
If we take 13 away from 20, we end up with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Going ahead to step 11:
When dividing 70 by 13, we get 5 with a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 3984959.615
If we subtract 65 from 70, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

On to step 12:
If we divide 50 by 13, we get 3 and a remainder of 11.
The number 3 becomes the next digit in our result. 
Result so far: 3984959.6153
If we subtract 39 from 50, we get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 13:
13 goes into 110 8 times with a remainder of 6.
Use 8 as the next digit of our solution. 
Result so far: 3984959.61538
Subtract 104 from 110 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Going ahead to step 14:
If we divide 60 by 13, we get 4 and a remainder of 8.
The number 4 becomes the next digit in our result. 
Result so far: 3984959.615384
The remainder is 8 after subtracting 52 from 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

On to step 15:
13 can be fit into 80 6 times, resulting in a remainder of 2.
The next digit of our result is 6. 
Result so far: 3984959.6153846
The remainder is 2 after subtracting 78 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Step 16:
13 goes into 20 1 times with a remainder of 7.
Put 1 as the next digit of the answer. 
Result so far: 3984959.61538461
Subtracting 13 from 20 leaves us with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

After the division, we end up with 3984959.61538461 and a remainder of 7e-09.