Let's divide 171991 by 81
Our goal is to divide 171991 by 81.

Moving on to step 1:
When dividing 1 by 81, we get 0 with a remainder of 1.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 1, we end up with 1.
Append the next digit (7) from the dividend to 1 and continue with: 17 / 81

Moving on to step 2:
17 divided by 81 is 0 with a remainder of 17.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 17 after subtracting 0 from 17.
Grab the next digit (1) from the dividend, add it to 17, then carry on: 171 / 81

Moving on to step 3:
81 can be fit into 171 2 times, resulting in a remainder of 9.
The next digit of our result is 2. 
Result so far: 2.0
Deduct 162 from 171 and we're left with 9.
Append the next digit (9) from the dividend to 9 and continue with: 99 / 81

On to step 4:
If we divide 99 by 81, we get 1 and a remainder of 18.
Use 1 as the next digit of our solution. 
Result so far: 21.0
The remainder is 18 after subtracting 81 from 99.
Fetch the next digit (9) from the dividend, attach it to 18 and continue: 189 / 81

Advancing to step 5:
81 goes into 189 2 times with a remainder of 27.
Write down 2 as next digit of the result. 
Result so far: 212.0
Subtracting 162 from 189 leaves us with 27.
Bring next digit (1) of the dividend behind the 27 and repeat the process: 271 / 81

Let's proceed to step 6:
81 goes into 271 3 times with a remainder of 28.
Write down 3 as next digit of the result. 
Result so far: 2123.0
Deduct 243 from 271 and we're left 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.

Moving on to step 7:
81 can be fit into 280 3 times, resulting in a remainder of 37.
Use 3 as the next digit of our solution. 
Result so far: 2123.3
Deduct 243 from 280 and we're left 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.

Going ahead to step 8:
81 goes into 370 4 times with a remainder of 46.
The next digit of our result is 4. 
Result so far: 2123.34
If we take 324 away from 370, we end up with 46.
Since there are no more digits in the dividend, we add a zero to the remainder making it 460, and continue the process.

Advancing to step 9:
When dividing 460 by 81, we get 5 with a remainder of 55.
Write down 5 as next digit of the result. 
Result so far: 2123.345
The remainder is 55 after subtracting 405 from 460.
Since there are no more digits in the dividend, we add a zero to the remainder making it 550, and continue the process.

Advancing to step 10:
When dividing 550 by 81, we get 6 with a remainder of 64.
Record the quotient 6 as the next digit in the result. 
Result so far: 2123.3456
Subtracting 486 from 550 leaves us with 64.
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 11:
If we divide 640 by 81, we get 7 and a remainder of 73.
Use 7 as the next digit of our solution. 
Result so far: 2123.34567
The remainder is 73 after subtracting 567 from 640.
Since there are no more digits in the dividend, we add a zero to the remainder making it 730, and continue the process.

Going ahead to step 12:
The number 81 fits into 730 9 times, leaving a remainder of 1.
The next digit of our result is 9. 
Result so far: 2123.345679
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.

Step 13:
If we divide 10 by 81, we get 0 and a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 2123.345679
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 14:
100 divided by 81 is 1 with a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 2123.34567901
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.

The quotient of the division is 2123.34567901, and the remainder is 1.9e-08.