We look at the division of 857213 by 25 
The aim is to understand the frequency of 25 in 857213.

Advancing to step 1:
The number 25 fits into 8 0 times, leaving a remainder of 8.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Include the next digit (5) from the dividend after 8, then repeat: 85 / 25

Moving on to step 2:
When dividing 85 by 25, we get 3 with a remainder of 10.
Put 3 as the next digit of the answer. 
Result so far: 3.0
If we take 75 away from 85, we end up with 10.
Fetch the next digit (7) from the dividend, attach it to 10 and continue: 107 / 25

Step 3:
107 divided by 25 is 4 with a remainder of 7.
Write down 4 as next digit of the result. 
Result so far: 34.0
Subtract 100 from 107 to get 7.
Fetch the next digit (2) from the dividend, attach it to 7 and continue: 72 / 25

Let's proceed to step 4:
25 goes into 72 2 times with a remainder of 22.
The number 2 becomes the next digit in our result. 
Result so far: 342.0
Subtract 50 from 72 to get 22.
Take the next digit (1) from the dividend and append it to 22, then repeat: 221 / 25

Step 5:
When dividing 221 by 25, we get 8 with a remainder of 21.
The number 8 becomes the next digit in our result. 
Result so far: 3428.0
The remainder is 21 after subtracting 200 from 221.
Include the next digit (3) from the dividend after 21, then repeat: 213 / 25

Moving on to step 6:
When dividing 213 by 25, we get 8 with a remainder of 13.
The number 8 becomes the next digit in our result. 
Result so far: 34288.0
Deduct 200 from 213 and we're left with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Advancing to step 7:
If we divide 130 by 25, we get 5 and a remainder of 5.
The next digit of our result is 5. 
Result so far: 34288.5
Subtract 125 from 130 to get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Let's proceed to step 8:
25 can be fit into 50 2 times, resulting in a remainder of 0.
Put 2 as the next digit of the answer. 
Result so far: 34288.52
Subtracting 50 from 50 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.

Advancing to step 9:
0 divided by 25 is 0 with a remainder of 0.
The next digit of our result is 0. 
Result so far: 34288.52
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.

Step 10:
If we divide 0 by 25, we get 0 and a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 34288.52
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.

After the division, we end up with 34288.52 and a remainder of 0.0.