424339 ÷ 12 
We're looking to find how many times 12 goes into 424339.

On to step 1:
4 divided by 12 is 0 with a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Include the next digit (2) from the dividend after 4, then repeat: 42 / 12

Going ahead to step 2:
12 can be fit into 42 3 times, resulting in a remainder of 6.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
If we take 36 away from 42, we end up with 6.
Bring next digit (4) of the dividend behind the 6 and repeat the process: 64 / 12

Let's proceed to step 3:
The number 12 fits into 64 5 times, leaving a remainder of 4.
The next digit of our result is 5. 
Result so far: 35.0
If we take 60 away from 64, we end up with 4.
Append the next digit (3) from the dividend to 4 and continue with: 43 / 12

Let's proceed to step 4:
The number 12 fits into 43 3 times, leaving a remainder of 7.
The next digit of our result is 3. 
Result so far: 353.0
Subtracting 36 from 43 leaves us with 7.
Fetch the next digit (3) from the dividend, attach it to 7 and continue: 73 / 12

Advancing to step 5:
If we divide 73 by 12, we get 6 and a remainder of 1.
The number 6 becomes the next digit in our result. 
Result so far: 3536.0
The remainder is 1 after subtracting 72 from 73.
Bring next digit (9) of the dividend behind the 1 and repeat the process: 19 / 12

Advancing to step 6:
19 divided by 12 is 1 with a remainder of 7.
Use 1 as the next digit of our solution. 
Result so far: 35361.0
The remainder is 7 after subtracting 12 from 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Moving on to step 7:
The number 12 fits into 70 5 times, leaving a remainder of 10.
Use 5 as the next digit of our solution. 
Result so far: 35361.5
The remainder is 10 after subtracting 60 from 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 8:
When dividing 100 by 12, we get 8 with a remainder of 4.
The next digit of our result is 8. 
Result so far: 35361.58
If we subtract 96 from 100, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Moving on to step 9:
If we divide 40 by 12, we get 3 and a remainder of 4.
The number 3 becomes the next digit in our result. 
Result so far: 35361.583
If we subtract 36 from 40, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 10:
When dividing 40 by 12, we get 3 with a remainder of 4.
Use 3 as the next digit of our solution. 
Result so far: 35361.5833
If we subtract 36 from 40, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

The final outcome is 35361.5833, with a leftover of 4e-05.