21025 divided by 15 
The aim is to understand the frequency of 15 in 21025.

Step 1:
15 can be fit into 2 0 times, resulting in a remainder of 2.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 2 leaves us with 2.
Include the next digit (1) from the dividend after 2, then repeat: 21 / 15

Step 2:
When dividing 21 by 15, we get 1 with a remainder of 6.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Deduct 15 from 21 and we're left with 6.
Fetch the next digit (0) from the dividend, attach it to 6 and continue: 60 / 15

Going ahead to step 3:
If we divide 60 by 15, we get 4 and a remainder of 0.
The next digit of our result is 4. 
Result so far: 14.0
If we take 60 away from 60, we end up with 0.
Append the next digit (2) from the dividend to 0 and continue with: 2 / 15

Let's proceed to step 4:
The number 15 fits into 2 0 times, leaving a remainder of 2.
The number 0 becomes the next digit in our result. 
Result so far: 140.0
Deduct 0 from 2 and we're left with 2.
Take the next digit (5) from the dividend and append it to 2, then repeat: 25 / 15

On to step 5:
If we divide 25 by 15, we get 1 and a remainder of 10.
Use 1 as the next digit of our solution. 
Result so far: 1401.0
If we take 15 away from 25, 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.

Advancing to step 6:
When dividing 100 by 15, we get 6 with a remainder of 10.
The number 6 becomes the next digit in our result. 
Result so far: 1401.6
Subtracting 90 from 100 leaves us 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.

On to step 7:
The number 15 fits into 100 6 times, leaving a remainder of 10.
The next digit of our result is 6. 
Result so far: 1401.66
Subtracting 90 from 100 leaves us 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.

In conclusion, the division gives 1401.66 with a balance of 0.01.