171912 ÷ 43 
We want to divide 171912 by 43.

On to step 1:
When dividing 1 by 43, we get 0 with a remainder of 1.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Append the next digit (7) from the dividend to 1 and continue with: 17 / 43

Moving on to step 2:
43 goes into 17 0 times with a remainder of 17.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 17 and we're left with 17.
Bring next digit (1) of the dividend behind the 17 and repeat the process: 171 / 43

Step 3:
The number 43 fits into 171 3 times, leaving a remainder of 42.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
Deduct 129 from 171 and we're left with 42.
Append the next digit (9) from the dividend to 42 and continue with: 429 / 43

Moving on to step 4:
When dividing 429 by 43, we get 9 with a remainder of 42.
Record the quotient 9 as the next digit in the result. 
Result so far: 39.0
If we subtract 387 from 429, we get 42.
Grab the next digit (1) from the dividend, add it to 42, then carry on: 421 / 43

Advancing to step 5:
43 can be fit into 421 9 times, resulting in a remainder of 34.
The number 9 becomes the next digit in our result. 
Result so far: 399.0
The remainder is 34 after subtracting 387 from 421.
Bring next digit (2) of the dividend behind the 34 and repeat the process: 342 / 43

Going ahead to step 6:
If we divide 342 by 43, we get 7 and a remainder of 41.
Write down 7 as next digit of the result. 
Result so far: 3997.0
Subtracting 301 from 342 leaves us with 41.
Since there are no more digits in the dividend, we add a zero to the remainder making it 410, and continue the process.

Going ahead to step 7:
If we divide 410 by 43, we get 9 and a remainder of 23.
Use 9 as the next digit of our solution. 
Result so far: 3997.9
If we take 387 away from 410, we end up with 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

On to step 8:
If we divide 230 by 43, we get 5 and a remainder of 15.
The number 5 becomes the next digit in our result. 
Result so far: 3997.95
Subtract 215 from 230 to get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Going ahead to step 9:
150 divided by 43 is 3 with a remainder of 21.
Write down 3 as next digit of the result. 
Result so far: 3997.953
If we take 129 away from 150, we end up with 21.
Since there are no more digits in the dividend, we add a zero to the remainder making it 210, and continue the process.

Step 10:
If we divide 210 by 43, we get 4 and a remainder of 38.
The next digit of our result is 4. 
Result so far: 3997.9534
Subtracting 172 from 210 leaves us with 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

On to step 11:
43 can be fit into 380 8 times, resulting in a remainder of 36.
Put 8 as the next digit of the answer. 
Result so far: 3997.95348
If we subtract 344 from 380, we get 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Step 12:
43 can be fit into 360 8 times, resulting in a remainder of 16.
The number 8 becomes the next digit in our result. 
Result so far: 3997.953488
If we take 344 away from 360, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

The final result is 3997.953488 with a remainder of 1.6e-06.