We're dividing 129984 by 20 
We're looking to find how many times 20 goes into 129984.

Step 1:
20 goes into 1 0 times with a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Fetch the next digit (2) from the dividend, attach it to 1 and continue: 12 / 20

Let's proceed to step 2:
If we divide 12 by 20, we get 0 and a remainder of 12.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 12, we get 12.
Take the next digit (9) from the dividend and append it to 12, then repeat: 129 / 20

Advancing to step 3:
If we divide 129 by 20, we get 6 and a remainder of 9.
The next digit of our result is 6. 
Result so far: 6.0
If we subtract 120 from 129, we get 9.
Include the next digit (9) from the dividend after 9, then repeat: 99 / 20

Advancing to step 4:
If we divide 99 by 20, we get 4 and a remainder of 19.
Put 4 as the next digit of the answer. 
Result so far: 64.0
The remainder is 19 after subtracting 80 from 99.
Bring next digit (8) of the dividend behind the 19 and repeat the process: 198 / 20

On to step 5:
20 can be fit into 198 9 times, resulting in a remainder of 18.
Record the quotient 9 as the next digit in the result. 
Result so far: 649.0
If we take 180 away from 198, we end up with 18.
Fetch the next digit (4) from the dividend, attach it to 18 and continue: 184 / 20

Advancing to step 6:
The number 20 fits into 184 9 times, leaving a remainder of 4.
The number 9 becomes the next digit in our result. 
Result so far: 6499.0
Deduct 180 from 184 and we're left with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Advancing to step 7:
40 divided by 20 is 2 with a remainder of 0.
Record the quotient 2 as the next digit in the result. 
Result so far: 6499.2
The remainder is 0 after subtracting 40 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 8:
If we divide 0 by 20, we get 0 and a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 6499.2
Subtracting 0 from 0 leaves us 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.

Moving on to step 9:
20 can be fit into 0 0 times, resulting in a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 6499.2
If we take 0 away from 0, we end up 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.

The final outcome is 6499.2, with a leftover of 0.0.