We divide 12173 by 21
Our goal is to divide 12173 by 21.

Let's proceed to step 1:
The number 21 fits into 1 0 times, leaving a remainder of 1.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 1 after subtracting 0 from 1.
Take the next digit (2) from the dividend and append it to 1, then repeat: 12 / 21

On to step 2:
When dividing 12 by 21, we get 0 with a remainder of 12.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 12 and we're left with 12.
Fetch the next digit (1) from the dividend, attach it to 12 and continue: 121 / 21

Advancing to step 3:
21 can be fit into 121 5 times, resulting in a remainder of 16.
The number 5 becomes the next digit in our result. 
Result so far: 5.0
If we subtract 105 from 121, we get 16.
Take the next digit (7) from the dividend and append it to 16, then repeat: 167 / 21

Going ahead to step 4:
21 goes into 167 7 times with a remainder of 20.
Write down 7 as next digit of the result. 
Result so far: 57.0
The remainder is 20 after subtracting 147 from 167.
Take the next digit (3) from the dividend and append it to 20, then repeat: 203 / 21

Step 5:
21 can be fit into 203 9 times, resulting in a remainder of 14.
The number 9 becomes the next digit in our result. 
Result so far: 579.0
Deduct 189 from 203 and we're left with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Moving on to step 6:
If we divide 140 by 21, we get 6 and a remainder of 14.
Record the quotient 6 as the next digit in the result. 
Result so far: 579.6
Subtracting 126 from 140 leaves us with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Step 7:
When dividing 140 by 21, we get 6 with a remainder of 14.
The next digit of our result is 6. 
Result so far: 579.66
Deduct 126 from 140 and we're left with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

The final result is 579.66 with a remainder of 0.014.