We look at the division of 638181 by 25 
The aim is to understand the frequency of 25 in 638181.

Going ahead to step 1:
If we divide 6 by 25, we get 0 and a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Take the next digit (3) from the dividend and append it to 6, then repeat: 63 / 25

On to step 2:
25 can be fit into 63 2 times, resulting in a remainder of 13.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
Subtract 50 from 63 to get 13.
Fetch the next digit (8) from the dividend, attach it to 13 and continue: 138 / 25

Advancing to step 3:
The number 25 fits into 138 5 times, leaving a remainder of 13.
Put 5 as the next digit of the answer. 
Result so far: 25.0
Subtract 125 from 138 to get 13.
Take the next digit (1) from the dividend and append it to 13, then repeat: 131 / 25

On to step 4:
25 can be fit into 131 5 times, resulting in a remainder of 6.
Put 5 as the next digit of the answer. 
Result so far: 255.0
If we subtract 125 from 131, we get 6.
Fetch the next digit (8) from the dividend, attach it to 6 and continue: 68 / 25

Going ahead to step 5:
The number 25 fits into 68 2 times, leaving a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 2552.0
Subtract 50 from 68 to get 18.
Take the next digit (1) from the dividend and append it to 18, then repeat: 181 / 25

Moving on to step 6:
When dividing 181 by 25, we get 7 with a remainder of 6.
The next digit of our result is 7. 
Result so far: 25527.0
The remainder is 6 after subtracting 175 from 181.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 7:
25 can be fit into 60 2 times, resulting in a remainder of 10.
The next digit of our result is 2. 
Result so far: 25527.2
If we subtract 50 from 60, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 8:
The number 25 fits into 100 4 times, leaving a remainder of 0.
The number 4 becomes the next digit in our result. 
Result so far: 25527.24
If we subtract 100 from 100, we get 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:
25 can be fit into 0 0 times, resulting in a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 25527.24
Deduct 0 from 0 and we're left 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.

Advancing to step 10:
25 can be fit into 0 0 times, resulting in a remainder of 0.
The next digit of our result is 0. 
Result so far: 25527.24
If we take 0 away from 0, we end up 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.

The quotient of the division is 25527.24, and the remainder is 0.0.