We look at the division of 815185 by 3 
The aim is to understand the frequency of 3 in 815185.

Going ahead to step 1:
The number 3 fits into 8 2 times, leaving a remainder of 2.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
Deduct 6 from 8 and we're left with 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 3

Let's proceed to step 2:
21 divided by 3 is 7 with a remainder of 0.
Record the quotient 7 as the next digit in the result. 
Result so far: 27.0
The remainder is 0 after subtracting 21 from 21.
Grab the next digit (5) from the dividend, add it to 0, then carry on: 5 / 3

Step 3:
5 divided by 3 is 1 with a remainder of 2.
Record the quotient 1 as the next digit in the result. 
Result so far: 271.0
Subtract 3 from 5 to get 2.
Grab the next digit (1) from the dividend, add it to 2, then carry on: 21 / 3

Step 4:
When dividing 21 by 3, we get 7 with a remainder of 0.
The next digit of our result is 7. 
Result so far: 2717.0
The remainder is 0 after subtracting 21 from 21.
Include the next digit (8) from the dividend after 0, then repeat: 8 / 3

Moving on to step 5:
If we divide 8 by 3, we get 2 and a remainder of 2.
Use 2 as the next digit of our solution. 
Result so far: 27172.0
Subtracting 6 from 8 leaves us with 2.
Include the next digit (5) from the dividend after 2, then repeat: 25 / 3

Going ahead to step 6:
3 can be fit into 25 8 times, resulting in a remainder of 1.
Use 8 as the next digit of our solution. 
Result so far: 271728.0
If we subtract 24 from 25, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Moving on to step 7:
When dividing 10 by 3, we get 3 with a remainder of 1.
Record the quotient 3 as the next digit in the result. 
Result so far: 271728.3
If we subtract 9 from 10, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Going ahead to step 8:
If we divide 10 by 3, we get 3 and a remainder of 1.
The next digit of our result is 3. 
Result so far: 271728.33
If we take 9 away from 10, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

The quotient of the division is 271728.33, and the remainder is 0.001.