171209 ÷ 85 
We want to divide 171209 by 85.

Advancing to step 1:
If we divide 1 by 85, we get 0 and a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 1 and we're left with 1.
Grab the next digit (7) from the dividend, add it to 1, then carry on: 17 / 85

Step 2:
85 goes into 17 0 times with a remainder of 17.
The number 0 becomes the next digit in our 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 / 85

Let's proceed to step 3:
If we divide 171 by 85, we get 2 and a remainder of 1.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
If we take 170 away from 171, we end up with 1.
Include the next digit (2) from the dividend after 1, then repeat: 12 / 85

Step 4:
If we divide 12 by 85, we get 0 and a remainder of 12.
Record the quotient 0 as the next digit in the result. 
Result so far: 20.0
If we take 0 away from 12, we end up with 12.
Take the next digit (0) from the dividend and append it to 12, then repeat: 120 / 85

On to step 5:
The number 85 fits into 120 1 times, leaving a remainder of 35.
The next digit of our result is 1. 
Result so far: 201.0
Deduct 85 from 120 and we're left with 35.
Fetch the next digit (9) from the dividend, attach it to 35 and continue: 359 / 85

Going ahead to step 6:
359 divided by 85 is 4 with a remainder of 19.
Write down 4 as next digit of the result. 
Result so far: 2014.0
Subtract 340 from 359 to get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Moving on to step 7:
85 goes into 190 2 times with a remainder of 20.
The number 2 becomes the next digit in our result. 
Result so far: 2014.2
If we subtract 170 from 190, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Advancing to step 8:
85 goes into 200 2 times with a remainder of 30.
Write down 2 as next digit of the result. 
Result so far: 2014.22
The remainder is 30 after subtracting 170 from 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

The final result is 2014.22 with a remainder of 0.03.