686559 ÷ 51 
The aim is to understand the frequency of 51 in 686559.

Going ahead to step 1:
51 can be fit into 6 0 times, resulting in a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 6 leaves us with 6.
Take the next digit (8) from the dividend and append it to 6, then repeat: 68 / 51

Moving on to step 2:
68 divided by 51 is 1 with a remainder of 17.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
If we take 51 away from 68, we end up with 17.
Grab the next digit (6) from the dividend, add it to 17, then carry on: 176 / 51

Moving on to step 3:
The number 51 fits into 176 3 times, leaving a remainder of 23.
Write down 3 as next digit of the result. 
Result so far: 13.0
If we take 153 away from 176, we end up with 23.
Bring next digit (5) of the dividend behind the 23 and repeat the process: 235 / 51

Step 4:
51 can be fit into 235 4 times, resulting in a remainder of 31.
The next digit of our result is 4. 
Result so far: 134.0
The remainder is 31 after subtracting 204 from 235.
Fetch the next digit (5) from the dividend, attach it to 31 and continue: 315 / 51

Moving on to step 5:
When dividing 315 by 51, we get 6 with a remainder of 9.
The next digit of our result is 6. 
Result so far: 1346.0
The remainder is 9 after subtracting 306 from 315.
Append the next digit (9) from the dividend to 9 and continue with: 99 / 51

Going ahead to step 6:
51 can be fit into 99 1 times, resulting in a remainder of 48.
The number 1 becomes the next digit in our result. 
Result so far: 13461.0
Subtracting 51 from 99 leaves us with 48.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

Going ahead to step 7:
When dividing 480 by 51, we get 9 with a remainder of 21.
Record the quotient 9 as the next digit in the result. 
Result so far: 13461.9
The remainder is 21 after subtracting 459 from 480.
Since there are no more digits in the dividend, we add a zero to the remainder making it 210, and continue the process.

On to step 8:
51 can be fit into 210 4 times, resulting in a remainder of 6.
Put 4 as the next digit of the answer. 
Result so far: 13461.94
Subtracting 204 from 210 leaves us with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

On to step 9:
51 can be fit into 60 1 times, resulting in a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 13461.941
Deduct 51 from 60 and we're left with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Step 10:
The number 51 fits into 90 1 times, leaving a remainder of 39.
Use 1 as the next digit of our solution. 
Result so far: 13461.9411
Subtracting 51 from 90 leaves us with 39.
Since there are no more digits in the dividend, we add a zero to the remainder making it 390, and continue the process.

After the division, we end up with 13461.9411 and a remainder of 0.00039.