We look at the division of 28773212 by 815 
The aim is to understand the frequency of 815 in 28773212.

Going ahead to step 1:
If we divide 2 by 815, we get 0 and a remainder of 2.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 2, we get 2.
Include the next digit (8) from the dividend after 2, then repeat: 28 / 815

Going ahead to step 2:
When dividing 28 by 815, we get 0 with a remainder of 28.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 28, we get 28.
Append the next digit (7) from the dividend to 28 and continue with: 287 / 815

Let's proceed to step 3:
287 divided by 815 is 0 with a remainder of 287.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 287 to get 287.
Bring next digit (7) of the dividend behind the 287 and repeat the process: 2877 / 815

Going ahead to step 4:
2877 divided by 815 is 3 with a remainder of 432.
Put 3 as the next digit of the answer. 
Result so far: 3.0
Subtract 2445 from 2877 to get 432.
Append the next digit (3) from the dividend to 432 and continue with: 4323 / 815

Let's proceed to step 5:
815 goes into 4323 5 times with a remainder of 248.
Write down 5 as next digit of the result. 
Result so far: 35.0
Subtracting 4075 from 4323 leaves us with 248.
Grab the next digit (2) from the dividend, add it to 248, then carry on: 2482 / 815

On to step 6:
2482 divided by 815 is 3 with a remainder of 37.
The number 3 becomes the next digit in our result. 
Result so far: 353.0
Deduct 2445 from 2482 and we're left with 37.
Include the next digit (1) from the dividend after 37, then repeat: 371 / 815

Moving on to step 7:
If we divide 371 by 815, we get 0 and a remainder of 371.
The next digit of our result is 0. 
Result so far: 3530.0
If we take 0 away from 371, we end up with 371.
Bring next digit (2) of the dividend behind the 371 and repeat the process: 3712 / 815

Moving on to step 8:
When dividing 3712 by 815, we get 4 with a remainder of 452.
Write down 4 as next digit of the result. 
Result so far: 35304.0
Deduct 3260 from 3712 and we're left with 452.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4520, and continue the process.

On to step 9:
4520 divided by 815 is 5 with a remainder of 445.
Record the quotient 5 as the next digit in the result. 
Result so far: 35304.5
If we take 4075 away from 4520, we end up with 445.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4450, and continue the process.

Moving on to step 10:
815 can be fit into 4450 5 times, resulting in a remainder of 375.
The number 5 becomes the next digit in our result. 
Result so far: 35304.55
The remainder is 375 after subtracting 4075 from 4450.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3750, and continue the process.

After the division, we end up with 35304.55 and a remainder of 0.375.