21129 divided by 9 
Our goal is to divide 21129 by 9.

Moving on to step 1:
When dividing 2 by 9, we get 0 with a remainder of 2.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 2, we get 2.
Grab the next digit (1) from the dividend, add it to 2, then carry on: 21 / 9

Moving on to step 2:
9 goes into 21 2 times with a remainder of 3.
Put 2 as the next digit of the answer. 
Result so far: 2.0
Subtract 18 from 21 to get 3.
Include the next digit (1) from the dividend after 3, then repeat: 31 / 9

Advancing to step 3:
If we divide 31 by 9, we get 3 and a remainder of 4.
The next digit of our result is 3. 
Result so far: 23.0
The remainder is 4 after subtracting 27 from 31.
Grab the next digit (2) from the dividend, add it to 4, then carry on: 42 / 9

Step 4:
42 divided by 9 is 4 with a remainder of 6.
Put 4 as the next digit of the answer. 
Result so far: 234.0
If we subtract 36 from 42, we get 6.
Append the next digit (9) from the dividend to 6 and continue with: 69 / 9

Advancing to step 5:
If we divide 69 by 9, we get 7 and a remainder of 6.
The next digit of our result is 7. 
Result so far: 2347.0
Subtracting 63 from 69 leaves us 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.

Let's proceed to step 6:
60 divided by 9 is 6 with a remainder of 6.
Use 6 as the next digit of our solution. 
Result so far: 2347.6
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:
If we divide 60 by 9, we get 6 and a remainder of 6.
Put 6 as the next digit of the answer. 
Result so far: 2347.66
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.

After the division, we end up with 2347.66 and a remainder of 0.006.