We're dividing 15489517 by 815 
The aim is to understand the frequency of 815 in 15489517.

Let's proceed to step 1:
If we divide 1 by 815, we get 0 and a remainder of 1.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 1 to get 1.
Take the next digit (5) from the dividend and append it to 1, then repeat: 15 / 815

On to step 2:
The number 815 fits into 15 0 times, leaving a remainder of 15.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 15, we get 15.
Append the next digit (4) from the dividend to 15 and continue with: 154 / 815

Moving on to step 3:
The number 815 fits into 154 0 times, leaving a remainder of 154.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 154 and we're left with 154.
Bring next digit (8) of the dividend behind the 154 and repeat the process: 1548 / 815

Let's proceed to step 4:
When dividing 1548 by 815, we get 1 with a remainder of 733.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we subtract 815 from 1548, we get 733.
Fetch the next digit (9) from the dividend, attach it to 733 and continue: 7339 / 815

Moving on to step 5:
The number 815 fits into 7339 9 times, leaving a remainder of 4.
The next digit of our result is 9. 
Result so far: 19.0
Deduct 7335 from 7339 and we're left with 4.
Append the next digit (5) from the dividend to 4 and continue with: 45 / 815

Moving on to step 6:
If we divide 45 by 815, we get 0 and a remainder of 45.
Record the quotient 0 as the next digit in the result. 
Result so far: 190.0
Deduct 0 from 45 and we're left with 45.
Fetch the next digit (1) from the dividend, attach it to 45 and continue: 451 / 815

Moving on to step 7:
The number 815 fits into 451 0 times, leaving a remainder of 451.
The number 0 becomes the next digit in our result. 
Result so far: 1900.0
Deduct 0 from 451 and we're left with 451.
Bring next digit (7) of the dividend behind the 451 and repeat the process: 4517 / 815

Moving on to step 8:
815 goes into 4517 5 times with a remainder of 442.
Use 5 as the next digit of our solution. 
Result so far: 19005.0
If we subtract 4075 from 4517, we get 442.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4420, and continue the process.

Step 9:
If we divide 4420 by 815, we get 5 and a remainder of 345.
Write down 5 as next digit of the result. 
Result so far: 19005.5
Deduct 4075 from 4420 and we're left with 345.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3450, and continue the process.

On to step 10:
When dividing 3450 by 815, we get 4 with a remainder of 190.
The next digit of our result is 4. 
Result so far: 19005.54
If we take 3260 away from 3450, we end up with 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1900, and continue the process.

Advancing to step 11:
The number 815 fits into 1900 2 times, leaving a remainder of 270.
Use 2 as the next digit of our solution. 
Result so far: 19005.542
If we take 1630 away from 1900, we end up with 270.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2700, and continue the process.

Moving on to step 12:
2700 divided by 815 is 3 with a remainder of 255.
Write down 3 as next digit of the result. 
Result so far: 19005.5423
If we subtract 2445 from 2700, we get 255.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2550, and continue the process.

Moving on to step 13:
The number 815 fits into 2550 3 times, leaving a remainder of 105.
The next digit of our result is 3. 
Result so far: 19005.54233
Subtract 2445 from 2550 to get 105.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1050, and continue the process.

The final result is 19005.54233 with a remainder of 0.000105.