We look at the division of 23991 by 9 
We want to divide 23991 by 9.

Going ahead to step 1:
When dividing 2 by 9, we get 0 with a remainder of 2.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 2 after subtracting 0 from 2.
Fetch the next digit (3) from the dividend, attach it to 2 and continue: 23 / 9

Let's proceed to step 2:
If we divide 23 by 9, we get 2 and a remainder of 5.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
Deduct 18 from 23 and we're left with 5.
Append the next digit (9) from the dividend to 5 and continue with: 59 / 9

Step 3:
The number 9 fits into 59 6 times, leaving a remainder of 5.
Put 6 as the next digit of the answer. 
Result so far: 26.0
The remainder is 5 after subtracting 54 from 59.
Append the next digit (9) from the dividend to 5 and continue with: 59 / 9

Step 4:
When dividing 59 by 9, we get 6 with a remainder of 5.
Write down 6 as next digit of the result. 
Result so far: 266.0
Deduct 54 from 59 and we're left with 5.
Bring next digit (1) of the dividend behind the 5 and repeat the process: 51 / 9

Moving on to step 5:
9 can be fit into 51 5 times, resulting in a remainder of 6.
Write down 5 as next digit of the result. 
Result so far: 2665.0
If we take 45 away from 51, we end up with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Moving on to step 6:
9 can be fit into 60 6 times, resulting in a remainder of 6.
Put 6 as the next digit of the answer. 
Result so far: 2665.6
Deduct 54 from 60 and we're left with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Moving on to step 7:
9 goes into 60 6 times with a remainder of 6.
Write down 6 as next digit of the result. 
Result so far: 2665.66
Subtract 54 from 60 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Our division results in 2665.66 with a remaining 0.006.