We're dividing 51209 by 55 
The aim is to understand the frequency of 55 in 51209.

Advancing to step 1:
The number 55 fits into 5 0 times, leaving a remainder of 5.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 5 leaves us with 5.
Fetch the next digit (1) from the dividend, attach it to 5 and continue: 51 / 55

Moving on to step 2:
55 can be fit into 51 0 times, resulting in a remainder of 51.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 51, we get 51.
Fetch the next digit (2) from the dividend, attach it to 51 and continue: 512 / 55

On to step 3:
512 divided by 55 is 9 with a remainder of 17.
Use 9 as the next digit of our solution. 
Result so far: 9.0
Subtracting 495 from 512 leaves us with 17.
Grab the next digit (0) from the dividend, add it to 17, then carry on: 170 / 55

Let's proceed to step 4:
If we divide 170 by 55, we get 3 and a remainder of 5.
The next digit of our result is 3. 
Result so far: 93.0
Deduct 165 from 170 and we're left with 5.
Append the next digit (9) from the dividend to 5 and continue with: 59 / 55

Let's proceed to step 5:
If we divide 59 by 55, we get 1 and a remainder of 4.
Put 1 as the next digit of the answer. 
Result so far: 931.0
Subtract 55 from 59 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.

Let's proceed to step 6:
55 can be fit into 40 0 times, resulting in a remainder of 40.
The number 0 becomes the next digit in our result. 
Result so far: 931.0
Subtracting 0 from 40 leaves us with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Let's proceed to step 7:
When dividing 400 by 55, we get 7 with a remainder of 15.
The number 7 becomes the next digit in our result. 
Result so far: 931.07
The remainder is 15 after subtracting 385 from 400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Moving on to step 8:
55 can be fit into 150 2 times, resulting in a remainder of 40.
The next digit of our result is 2. 
Result so far: 931.072
If we subtract 110 from 150, we get 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Step 9:
55 can be fit into 400 7 times, resulting in a remainder of 15.
Write down 7 as next digit of the result. 
Result so far: 931.0727
If we take 385 away from 400, we end up with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Let's proceed to step 10:
The number 55 fits into 150 2 times, leaving a remainder of 40.
Put 2 as the next digit of the answer. 
Result so far: 931.07272
Deduct 110 from 150 and we're left with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Moving on to step 11:
55 goes into 400 7 times with a remainder of 15.
Record the quotient 7 as the next digit in the result. 
Result so far: 931.072727
Deduct 385 from 400 and we're left with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Step 12:
55 goes into 150 2 times with a remainder of 40.
Use 2 as the next digit of our solution. 
Result so far: 931.0727272
The remainder is 40 after subtracting 110 from 150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Going ahead to step 13:
When dividing 400 by 55, we get 7 with a remainder of 15.
Use 7 as the next digit of our solution. 
Result so far: 931.07272727
If we take 385 away from 400, we end up with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

The final result is 931.07272727 with a remainder of 1.5e-08.