We look at the division of 519729 by 3 
The aim is to understand the frequency of 3 in 519729.

Step 1:
If we divide 5 by 3, we get 1 and a remainder of 2.
Put 1 as the next digit of the answer. 
Result so far: 1.0
Subtract 3 from 5 to get 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 3

Going ahead 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: 17.0
If we take 21 away from 21, we end up with 0.
Grab the next digit (9) from the dividend, add it to 0, then carry on: 9 / 3

Step 3:
9 divided by 3 is 3 with a remainder of 0.
The next digit of our result is 3. 
Result so far: 173.0
The remainder is 0 after subtracting 9 from 9.
Take the next digit (7) from the dividend and append it to 0, then repeat: 7 / 3

Let's proceed to step 4:
If we divide 7 by 3, we get 2 and a remainder of 1.
Put 2 as the next digit of the answer. 
Result so far: 1732.0
Subtracting 6 from 7 leaves us with 1.
Bring next digit (2) of the dividend behind the 1 and repeat the process: 12 / 3

Going ahead to step 5:
When dividing 12 by 3, we get 4 with a remainder of 0.
Use 4 as the next digit of our solution. 
Result so far: 17324.0
Subtracting 12 from 12 leaves us with 0.
Bring next digit (9) of the dividend behind the 0 and repeat the process: 9 / 3

Advancing to step 6:
When dividing 9 by 3, we get 3 with a remainder of 0.
Record the quotient 3 as the next digit in the result. 
Result so far: 173243.0
Subtracting 9 from 9 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 7:
If we divide 0 by 3, we get 0 and a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 173243.0
Subtract 0 from 0 to get 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 8:
The number 3 fits into 0 0 times, leaving a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 173243.0
Deduct 0 from 0 and we're left 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.

The final result is 173243.0 with a remainder of 0.0.