We're dividing 339611 by 86 
We want to divide 339611 by 86.

Step 1:
86 goes into 3 0 times with a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Take the next digit (3) from the dividend and append it to 3, then repeat: 33 / 86

On to step 2:
If we divide 33 by 86, we get 0 and a remainder of 33.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 33, we get 33.
Grab the next digit (9) from the dividend, add it to 33, then carry on: 339 / 86

Advancing to step 3:
339 divided by 86 is 3 with a remainder of 81.
Put 3 as the next digit of the answer. 
Result so far: 3.0
If we take 258 away from 339, we end up with 81.
Fetch the next digit (6) from the dividend, attach it to 81 and continue: 816 / 86

Advancing to step 4:
The number 86 fits into 816 9 times, leaving a remainder of 42.
The next digit of our result is 9. 
Result so far: 39.0
If we subtract 774 from 816, we get 42.
Fetch the next digit (1) from the dividend, attach it to 42 and continue: 421 / 86

Going ahead to step 5:
If we divide 421 by 86, we get 4 and a remainder of 77.
The number 4 becomes the next digit in our result. 
Result so far: 394.0
Subtract 344 from 421 to get 77.
Include the next digit (1) from the dividend after 77, then repeat: 771 / 86

Let's proceed to step 6:
86 can be fit into 771 8 times, resulting in a remainder of 83.
Record the quotient 8 as the next digit in the result. 
Result so far: 3948.0
The remainder is 83 after subtracting 688 from 771.
Since there are no more digits in the dividend, we add a zero to the remainder making it 830, and continue the process.

Advancing to step 7:
86 goes into 830 9 times with a remainder of 56.
Write down 9 as next digit of the result. 
Result so far: 3948.9
Deduct 774 from 830 and we're left with 56.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

Going ahead to step 8:
The number 86 fits into 560 6 times, leaving a remainder of 44.
The next digit of our result is 6. 
Result so far: 3948.96
Subtracting 516 from 560 leaves us with 44.
Since there are no more digits in the dividend, we add a zero to the remainder making it 440, and continue the process.

Let's proceed to step 9:
440 divided by 86 is 5 with a remainder of 10.
Write down 5 as next digit of the result. 
Result so far: 3948.965
If we take 430 away from 440, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Step 10:
If we divide 100 by 86, we get 1 and a remainder of 14.
Put 1 as the next digit of the answer. 
Result so far: 3948.9651
Subtract 86 from 100 to get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Going ahead to step 11:
If we divide 140 by 86, we get 1 and a remainder of 54.
Put 1 as the next digit of the answer. 
Result so far: 3948.96511
If we subtract 86 from 140, we get 54.
Since there are no more digits in the dividend, we add a zero to the remainder making it 540, and continue the process.

The final outcome is 3948.96511, with a leftover of 5.4e-05.