We look at the division of 172440 by 12 
We want to divide 172440 by 12.

Step 1:
If we divide 1 by 12, we get 0 and a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 1, we end up with 1.
Take the next digit (7) from the dividend and append it to 1, then repeat: 17 / 12

Step 2:
17 divided by 12 is 1 with a remainder of 5.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Subtract 12 from 17 to get 5.
Fetch the next digit (2) from the dividend, attach it to 5 and continue: 52 / 12

Let's proceed to step 3:
The number 12 fits into 52 4 times, leaving a remainder of 4.
Record the quotient 4 as the next digit in the result. 
Result so far: 14.0
Subtracting 48 from 52 leaves us with 4.
Bring next digit (4) of the dividend behind the 4 and repeat the process: 44 / 12

Step 4:
44 divided by 12 is 3 with a remainder of 8.
The number 3 becomes the next digit in our result. 
Result so far: 143.0
The remainder is 8 after subtracting 36 from 44.
Append the next digit (4) from the dividend to 8 and continue with: 84 / 12

Advancing to step 5:
If we divide 84 by 12, we get 7 and a remainder of 0.
The next digit of our result is 7. 
Result so far: 1437.0
If we subtract 84 from 84, we get 0.
Include the next digit (0) from the dividend after 0, then repeat: 0 / 12

Step 6:
The number 12 fits into 0 0 times, leaving a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 14370.0
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 7:
If we divide 0 by 12, we get 0 and a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 14370.0
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Advancing to step 8:
If we divide 0 by 12, we get 0 and a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 14370.0
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Our division results in 14370.0 with a remaining 0.0.