Let's divide 126339 by 3
The aim is to understand the frequency of 3 in 126339.

Advancing to step 1:
When dividing 1 by 3, we get 0 with a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 1 and we're left with 1.
Take the next digit (2) from the dividend and append it to 1, then repeat: 12 / 3

Let's proceed to step 2:
3 goes into 12 4 times with a remainder of 0.
Use 4 as the next digit of our solution. 
Result so far: 4.0
Subtract 12 from 12 to get 0.
Fetch the next digit (6) from the dividend, attach it to 0 and continue: 6 / 3

Moving on to step 3:
6 divided by 3 is 2 with a remainder of 0.
Write down 2 as next digit of the result. 
Result so far: 42.0
Subtract 6 from 6 to get 0.
Take the next digit (3) from the dividend and append it to 0, then repeat: 3 / 3

Going ahead to step 4:
If we divide 3 by 3, we get 1 and a remainder of 0.
Write down 1 as next digit of the result. 
Result so far: 421.0
If we take 3 away from 3, we end up with 0.
Grab the next digit (3) from the dividend, add it to 0, then carry on: 3 / 3

Let's proceed to step 5:
When dividing 3 by 3, we get 1 with a remainder of 0.
The next digit of our result is 1. 
Result so far: 4211.0
The remainder is 0 after subtracting 3 from 3.
Grab the next digit (9) from the dividend, add it to 0, then carry on: 9 / 3

Let's proceed to step 6:
3 can be fit into 9 3 times, resulting in a remainder of 0.
The number 3 becomes the next digit in our result. 
Result so far: 42113.0
If we subtract 9 from 9, we 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.

Going ahead to step 7:
3 goes into 0 0 times with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 42113.0
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Step 8:
The number 3 fits into 0 0 times, leaving a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 42113.0
If we subtract 0 from 0, we 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.

The final outcome is 42113.0, with a leftover of 0.0.