25780938 ÷ 686 
The aim is to understand the frequency of 686 in 25780938.

Let's proceed to step 1:
686 can be fit into 2 0 times, resulting in a remainder of 2.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 2, we get 2.
Take the next digit (5) from the dividend and append it to 2, then repeat: 25 / 686

On to step 2:
686 goes into 25 0 times with a remainder of 25.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 25 and we're left with 25.
Bring next digit (7) of the dividend behind the 25 and repeat the process: 257 / 686

Going ahead to step 3:
If we divide 257 by 686, we get 0 and a remainder of 257.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 257 leaves us with 257.
Include the next digit (8) from the dividend after 257, then repeat: 2578 / 686

On to step 4:
686 goes into 2578 3 times with a remainder of 520.
The next digit of our result is 3. 
Result so far: 3.0
Deduct 2058 from 2578 and we're left with 520.
Grab the next digit (0) from the dividend, add it to 520, then carry on: 5200 / 686

Step 5:
When dividing 5200 by 686, we get 7 with a remainder of 398.
Put 7 as the next digit of the answer. 
Result so far: 37.0
Deduct 4802 from 5200 and we're left with 398.
Include the next digit (9) from the dividend after 398, then repeat: 3989 / 686

Let's proceed to step 6:
686 goes into 3989 5 times with a remainder of 559.
Write down 5 as next digit of the result. 
Result so far: 375.0
Subtracting 3430 from 3989 leaves us with 559.
Include the next digit (3) from the dividend after 559, then repeat: 5593 / 686

Advancing to step 7:
When dividing 5593 by 686, we get 8 with a remainder of 105.
Write down 8 as next digit of the result. 
Result so far: 3758.0
Subtracting 5488 from 5593 leaves us with 105.
Include the next digit (8) from the dividend after 105, then repeat: 1058 / 686

Let's proceed to step 8:
The number 686 fits into 1058 1 times, leaving a remainder of 372.
The next digit of our result is 1. 
Result so far: 37581.0
Subtract 686 from 1058 to get 372.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3720, and continue the process.

Let's proceed to step 9:
686 goes into 3720 5 times with a remainder of 290.
Record the quotient 5 as the next digit in the result. 
Result so far: 37581.5
Deduct 3430 from 3720 and we're left with 290.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2900, and continue the process.

Moving on to step 10:
The number 686 fits into 2900 4 times, leaving a remainder of 156.
Use 4 as the next digit of our solution. 
Result so far: 37581.54
If we subtract 2744 from 2900, we get 156.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1560, and continue the process.

Step 11:
1560 divided by 686 is 2 with a remainder of 188.
Use 2 as the next digit of our solution. 
Result so far: 37581.542
If we take 1372 away from 1560, we end up with 188.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1880, and continue the process.

Advancing to step 12:
If we divide 1880 by 686, we get 2 and a remainder of 508.
Put 2 as the next digit of the answer. 
Result so far: 37581.5422
If we subtract 1372 from 1880, we get 508.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5080, and continue the process.

The final outcome is 37581.5422, with a leftover of 0.00508.