We look at the division of 42086 by 86 
We're looking to find how many times 86 goes into 42086.

Step 1:
86 can be fit into 4 0 times, resulting in a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 4, we get 4.
Fetch the next digit (2) from the dividend, attach it to 4 and continue: 42 / 86

Moving on to step 2:
42 divided by 86 is 0 with a remainder of 42.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 42 leaves us with 42.
Include the next digit (0) from the dividend after 42, then repeat: 420 / 86

Advancing to step 3:
420 divided by 86 is 4 with a remainder of 76.
The number 4 becomes the next digit in our result. 
Result so far: 4.0
If we take 344 away from 420, we end up with 76.
Bring next digit (8) of the dividend behind the 76 and repeat the process: 768 / 86

On to step 4:
If we divide 768 by 86, we get 8 and a remainder of 80.
Put 8 as the next digit of the answer. 
Result so far: 48.0
The remainder is 80 after subtracting 688 from 768.
Bring next digit (6) of the dividend behind the 80 and repeat the process: 806 / 86

Moving on to step 5:
806 divided by 86 is 9 with a remainder of 32.
The next digit of our result is 9. 
Result so far: 489.0
Deduct 774 from 806 and we're left with 32.
Since there are no more digits in the dividend, we add a zero to the remainder making it 320, and continue the process.

Step 6:
When dividing 320 by 86, we get 3 with a remainder of 62.
Put 3 as the next digit of the answer. 
Result so far: 489.3
Subtracting 258 from 320 leaves us with 62.
Since there are no more digits in the dividend, we add a zero to the remainder making it 620, and continue the process.

Step 7:
The number 86 fits into 620 7 times, leaving a remainder of 18.
Write down 7 as next digit of the result. 
Result so far: 489.37
Subtracting 602 from 620 leaves us with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Advancing to step 8:
The number 86 fits into 180 2 times, leaving a remainder of 8.
The next digit of our result is 2. 
Result so far: 489.372
If we subtract 172 from 180, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 9:
86 can be fit into 80 0 times, resulting in a remainder of 80.
Write down 0 as next digit of the result. 
Result so far: 489.372
The remainder is 80 after subtracting 0 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 800, and continue the process.

Moving on to step 10:
The number 86 fits into 800 9 times, leaving a remainder of 26.
The number 9 becomes the next digit in our result. 
Result so far: 489.37209
If we subtract 774 from 800, we get 26.
Since there are no more digits in the dividend, we add a zero to the remainder making it 260, and continue the process.

Going ahead to step 11:
260 divided by 86 is 3 with a remainder of 2.
The number 3 becomes the next digit in our result. 
Result so far: 489.372093
If we take 258 away from 260, we end up with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Going ahead to step 12:
86 can be fit into 20 0 times, resulting in a remainder of 20.
Record the quotient 0 as the next digit in the result. 
Result so far: 489.372093
Subtracting 0 from 20 leaves us with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Step 13:
86 can be fit into 200 2 times, resulting in a remainder of 28.
Write down 2 as next digit of the result. 
Result so far: 489.37209302
Subtracting 172 from 200 leaves us with 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

The final result is 489.37209302 with a remainder of 2.8e-08.