We divide 431839 by 3
The aim is to understand the frequency of 3 in 431839.

Step 1:
3 can be fit into 4 1 times, resulting in a remainder of 1.
Put 1 as the next digit of the answer. 
Result so far: 1.0
The remainder is 1 after subtracting 3 from 4.
Append the next digit (3) from the dividend to 1 and continue with: 13 / 3

Moving on to step 2:
If we divide 13 by 3, we get 4 and a remainder of 1.
The next digit of our result is 4. 
Result so far: 14.0
Subtract 12 from 13 to get 1.
Include the next digit (1) from the dividend after 1, then repeat: 11 / 3

Step 3:
3 goes into 11 3 times with a remainder of 2.
The next digit of our result is 3. 
Result so far: 143.0
The remainder is 2 after subtracting 9 from 11.
Fetch the next digit (8) from the dividend, attach it to 2 and continue: 28 / 3

Moving on to step 4:
3 can be fit into 28 9 times, resulting in a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 1439.0
If we take 27 away from 28, we end up with 1.
Take the next digit (3) from the dividend and append it to 1, then repeat: 13 / 3

Step 5:
When dividing 13 by 3, we get 4 with a remainder of 1.
Record the quotient 4 as the next digit in the result. 
Result so far: 14394.0
Deduct 12 from 13 and we're left with 1.
Grab the next digit (9) from the dividend, add it to 1, then carry on: 19 / 3

Going ahead to step 6:
3 goes into 19 6 times with a remainder of 1.
Write down 6 as next digit of the result. 
Result so far: 143946.0
If we subtract 18 from 19, 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.

On to step 7:
The number 3 fits into 10 3 times, leaving a remainder of 1.
The next digit of our result is 3. 
Result so far: 143946.3
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:
When dividing 10 by 3, we get 3 with a remainder of 1.
The number 3 becomes the next digit in our result. 
Result so far: 143946.33
Deduct 9 from 10 and we're left 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 final outcome is 143946.33, with a leftover of 0.001.