We look at the division of 6500678 by 686 
The aim is to understand the frequency of 686 in 6500678.

On to step 1:
6 divided by 686 is 0 with a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Include the next digit (5) from the dividend after 6, then repeat: 65 / 686

Going ahead to step 2:
The number 686 fits into 65 0 times, leaving a remainder of 65.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 65, we get 65.
Bring next digit (0) of the dividend behind the 65 and repeat the process: 650 / 686

On to step 3:
When dividing 650 by 686, we get 0 with a remainder of 650.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 650 to get 650.
Include the next digit (0) from the dividend after 650, then repeat: 6500 / 686

Let's proceed to step 4:
686 goes into 6500 9 times with a remainder of 326.
Put 9 as the next digit of the answer. 
Result so far: 9.0
The remainder is 326 after subtracting 6174 from 6500.
Grab the next digit (6) from the dividend, add it to 326, then carry on: 3266 / 686

Going ahead to step 5:
If we divide 3266 by 686, we get 4 and a remainder of 522.
The next digit of our result is 4. 
Result so far: 94.0
If we take 2744 away from 3266, we end up with 522.
Fetch the next digit (7) from the dividend, attach it to 522 and continue: 5227 / 686

Let's proceed to step 6:
The number 686 fits into 5227 7 times, leaving a remainder of 425.
Write down 7 as next digit of the result. 
Result so far: 947.0
If we take 4802 away from 5227, we end up with 425.
Include the next digit (8) from the dividend after 425, then repeat: 4258 / 686

Advancing to step 7:
The number 686 fits into 4258 6 times, leaving a remainder of 142.
Put 6 as the next digit of the answer. 
Result so far: 9476.0
If we take 4116 away from 4258, we end up with 142.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1420, and continue the process.

Let's proceed to step 8:
686 can be fit into 1420 2 times, resulting in a remainder of 48.
Use 2 as the next digit of our solution. 
Result so far: 9476.2
The remainder is 48 after subtracting 1372 from 1420.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

Step 9:
480 divided by 686 is 0 with a remainder of 480.
Write down 0 as next digit of the result. 
Result so far: 9476.2
Subtract 0 from 480 to get 480.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4800, and continue the process.

Step 10:
4800 divided by 686 is 6 with a remainder of 684.
The number 6 becomes the next digit in our result. 
Result so far: 9476.206
Deduct 4116 from 4800 and we're left with 684.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6840, and continue the process.

Advancing to step 11:
686 can be fit into 6840 9 times, resulting in a remainder of 666.
The number 9 becomes the next digit in our result. 
Result so far: 9476.2069
If we subtract 6174 from 6840, we get 666.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6660, and continue the process.

Step 12:
6660 divided by 686 is 9 with a remainder of 486.
Write down 9 as next digit of the result. 
Result so far: 9476.20699
Deduct 6174 from 6660 and we're left with 486.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4860, and continue the process.

Our division results in 9476.20699 with a remaining 0.000486.