We divide 615999 by 25
The aim is to understand the frequency of 25 in 615999.

Let's proceed to step 1:
If we divide 6 by 25, we get 0 and a remainder of 6.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Take the next digit (1) from the dividend and append it to 6, then repeat: 61 / 25

Moving on to step 2:
When dividing 61 by 25, we get 2 with a remainder of 11.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
Deduct 50 from 61 and we're left with 11.
Fetch the next digit (5) from the dividend, attach it to 11 and continue: 115 / 25

On to step 3:
25 goes into 115 4 times with a remainder of 15.
The next digit of our result is 4. 
Result so far: 24.0
Deduct 100 from 115 and we're left with 15.
Append the next digit (9) from the dividend to 15 and continue with: 159 / 25

Advancing to step 4:
25 goes into 159 6 times with a remainder of 9.
The number 6 becomes the next digit in our result. 
Result so far: 246.0
Deduct 150 from 159 and we're left with 9.
Bring next digit (9) of the dividend behind the 9 and repeat the process: 99 / 25

On to step 5:
99 divided by 25 is 3 with a remainder of 24.
Write down 3 as next digit of the result. 
Result so far: 2463.0
The remainder is 24 after subtracting 75 from 99.
Bring next digit (9) of the dividend behind the 24 and repeat the process: 249 / 25

On to step 6:
25 goes into 249 9 times with a remainder of 24.
Write down 9 as next digit of the result. 
Result so far: 24639.0
If we subtract 225 from 249, we get 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

On to step 7:
When dividing 240 by 25, we get 9 with a remainder of 15.
Write down 9 as next digit of the result. 
Result so far: 24639.9
Subtracting 225 from 240 leaves us with 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:
The number 25 fits into 150 6 times, leaving a remainder of 0.
Write down 6 as next digit of the result. 
Result so far: 24639.96
If we subtract 150 from 150, 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.

Step 9:
25 can be fit into 0 0 times, resulting in a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 24639.96
If we subtract 0 from 0, 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.

Step 10:
If we divide 0 by 25, we get 0 and a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 24639.96
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.

Our division results in 24639.96 with a remaining 0.0.