We're dividing 400631 by 25 
The aim is to understand the frequency of 25 in 400631.

Advancing to step 1:
25 can be fit into 4 0 times, resulting in a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Fetch the next digit (0) from the dividend, attach it to 4 and continue: 40 / 25

Advancing to step 2:
If we divide 40 by 25, we get 1 and a remainder of 15.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtract 25 from 40 to get 15.
Bring next digit (0) of the dividend behind the 15 and repeat the process: 150 / 25

Advancing to step 3:
When dividing 150 by 25, we get 6 with a remainder of 0.
Record the quotient 6 as the next digit in the result. 
Result so far: 16.0
Subtract 150 from 150 to get 0.
Append the next digit (6) from the dividend to 0 and continue with: 6 / 25

Let's proceed to step 4:
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: 160.0
Subtract 0 from 6 to get 6.
Bring next digit (3) of the dividend behind the 6 and repeat the process: 63 / 25

On to step 5:
25 goes into 63 2 times with a remainder of 13.
Write down 2 as next digit of the result. 
Result so far: 1602.0
If we subtract 50 from 63, we get 13.
Append the next digit (1) from the dividend to 13 and continue with: 131 / 25

Advancing to step 6:
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: 16025.0
If we take 125 away from 131, we end up 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 7:
The number 25 fits into 60 2 times, leaving a remainder of 10.
Use 2 as the next digit of our solution. 
Result so far: 16025.2
If we take 50 away from 60, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Step 8:
25 can be fit into 100 4 times, resulting in a remainder of 0.
Use 4 as the next digit of our solution. 
Result so far: 16025.24
The remainder is 0 after subtracting 100 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 9:
0 divided by 25 is 0 with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 16025.24
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.

Let's proceed to step 10:
The number 25 fits into 0 0 times, leaving a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 16025.24
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.

Our division results in 16025.24 with a remaining 0.0.