42431509 ÷ 81 
Our goal is to divide 42431509 by 81.

Moving on to step 1:
When dividing 4 by 81, we get 0 with a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 4 after subtracting 0 from 4.
Grab the next digit (2) from the dividend, add it to 4, then carry on: 42 / 81

Step 2:
81 can be fit into 42 0 times, resulting in a remainder of 42.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 42 to get 42.
Include the next digit (4) from the dividend after 42, then repeat: 424 / 81

On to step 3:
424 divided by 81 is 5 with a remainder of 19.
Use 5 as the next digit of our solution. 
Result so far: 5.0
If we subtract 405 from 424, we get 19.
Append the next digit (3) from the dividend to 19 and continue with: 193 / 81

On to step 4:
81 goes into 193 2 times with a remainder of 31.
Put 2 as the next digit of the answer. 
Result so far: 52.0
Deduct 162 from 193 and we're left with 31.
Fetch the next digit (1) from the dividend, attach it to 31 and continue: 311 / 81

Going ahead to step 5:
81 goes into 311 3 times with a remainder of 68.
Record the quotient 3 as the next digit in the result. 
Result so far: 523.0
Subtract 243 from 311 to get 68.
Take the next digit (5) from the dividend and append it to 68, then repeat: 685 / 81

Let's proceed to step 6:
When dividing 685 by 81, we get 8 with a remainder of 37.
Put 8 as the next digit of the answer. 
Result so far: 5238.0
If we take 648 away from 685, we end up with 37.
Include the next digit (0) from the dividend after 37, then repeat: 370 / 81

Advancing to step 7:
The number 81 fits into 370 4 times, leaving a remainder of 46.
Write down 4 as next digit of the result. 
Result so far: 52384.0
If we subtract 324 from 370, we get 46.
Include the next digit (9) from the dividend after 46, then repeat: 469 / 81

Let's proceed to step 8:
The number 81 fits into 469 5 times, leaving a remainder of 64.
The number 5 becomes the next digit in our result. 
Result so far: 523845.0
The remainder is 64 after subtracting 405 from 469.
Since there are no more digits in the dividend, we add a zero to the remainder making it 640, and continue the process.

Advancing to step 9:
640 divided by 81 is 7 with a remainder of 73.
Put 7 as the next digit of the answer. 
Result so far: 523845.7
If we subtract 567 from 640, we get 73.
Since there are no more digits in the dividend, we add a zero to the remainder making it 730, and continue the process.

Advancing to step 10:
If we divide 730 by 81, we get 9 and a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 523845.79
If we take 729 away from 730, we end up 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.

Moving on to step 11:
81 can be fit into 10 0 times, resulting in a remainder of 10.
The next digit of our result is 0. 
Result so far: 523845.79
The remainder is 10 after subtracting 0 from 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Moving on to step 12:
When dividing 100 by 81, we get 1 with a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 523845.7901
Subtracting 81 from 100 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Step 13:
If we divide 190 by 81, we get 2 and a remainder of 28.
The next digit of our result is 2. 
Result so far: 523845.79012
The remainder is 28 after subtracting 162 from 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

Advancing to step 14:
When dividing 280 by 81, we get 3 with a remainder of 37.
The next digit of our result is 3. 
Result so far: 523845.790123
If we take 243 away from 280, we end up with 37.
Since there are no more digits in the dividend, we add a zero to the remainder making it 370, and continue the process.

On to step 15:
If we divide 370 by 81, we get 4 and a remainder of 46.
Put 4 as the next digit of the answer. 
Result so far: 523845.7901234
Subtract 324 from 370 to get 46.
Since there are no more digits in the dividend, we add a zero to the remainder making it 460, and continue the process.

Step 16:
460 divided by 81 is 5 with a remainder of 55.
The next digit of our result is 5. 
Result so far: 523845.79012345
Deduct 405 from 460 and we're left with 55.
Since there are no more digits in the dividend, we add a zero to the remainder making it 550, and continue the process.

Our division results in 523845.79012345 with a remaining 5.5e-08.