We look at the division of 646394 by 25 
The aim is to understand the frequency of 25 in 646394.

Moving on to step 1:
The number 25 fits into 6 0 times, leaving a remainder of 6.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Append the next digit (4) from the dividend to 6 and continue with: 64 / 25

Let's proceed to step 2:
25 can be fit into 64 2 times, resulting in a remainder of 14.
The next digit of our result is 2. 
Result so far: 2.0
If we take 50 away from 64, we end up with 14.
Append the next digit (6) from the dividend to 14 and continue with: 146 / 25

Let's proceed to step 3:
The number 25 fits into 146 5 times, leaving a remainder of 21.
Use 5 as the next digit of our solution. 
Result so far: 25.0
The remainder is 21 after subtracting 125 from 146.
Grab the next digit (3) from the dividend, add it to 21, then carry on: 213 / 25

Going ahead to step 4:
When dividing 213 by 25, we get 8 with a remainder of 13.
Use 8 as the next digit of our solution. 
Result so far: 258.0
If we subtract 200 from 213, we get 13.
Append the next digit (9) from the dividend to 13 and continue with: 139 / 25

Advancing to step 5:
25 can be fit into 139 5 times, resulting in a remainder of 14.
Write down 5 as next digit of the result. 
Result so far: 2585.0
Subtracting 125 from 139 leaves us with 14.
Include the next digit (4) from the dividend after 14, then repeat: 144 / 25

On to step 6:
The number 25 fits into 144 5 times, leaving a remainder of 19.
Write down 5 as next digit of the result. 
Result so far: 25855.0
Subtract 125 from 144 to get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Going ahead to step 7:
The number 25 fits into 190 7 times, leaving a remainder of 15.
Record the quotient 7 as the next digit in the result. 
Result so far: 25855.7
Subtract 175 from 190 to get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Going ahead to step 8:
25 can be fit into 150 6 times, resulting in a remainder of 0.
Use 6 as the next digit of our solution. 
Result so far: 25855.76
Subtracting 150 from 150 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Going ahead to step 9:
If we divide 0 by 25, we get 0 and a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 25855.76
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 10:
25 can be fit into 0 0 times, resulting in a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 25855.76
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The quotient of the division is 25855.76, and the remainder is 0.0.