We're dividing 159809 by 20 
We want to figure out the number of times 159809 can be divided by 20.

On to step 1:
The number 20 fits into 1 0 times, leaving a remainder of 1.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 1, we get 1.
Grab the next digit (5) from the dividend, add it to 1, then carry on: 15 / 20

Moving on to step 2:
20 can be fit into 15 0 times, resulting in a remainder of 15.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 15 after subtracting 0 from 15.
Append the next digit (9) from the dividend to 15 and continue with: 159 / 20

Going ahead to step 3:
If we divide 159 by 20, we get 7 and a remainder of 19.
Put 7 as the next digit of the answer. 
Result so far: 7.0
Subtracting 140 from 159 leaves us with 19.
Include the next digit (8) from the dividend after 19, then repeat: 198 / 20

Advancing to step 4:
20 can be fit into 198 9 times, resulting in a remainder of 18.
Use 9 as the next digit of our solution. 
Result so far: 79.0
If we subtract 180 from 198, we get 18.
Bring next digit (0) of the dividend behind the 18 and repeat the process: 180 / 20

Advancing to step 5:
20 can be fit into 180 9 times, resulting in a remainder of 0.
The next digit of our result is 9. 
Result so far: 799.0
If we take 180 away from 180, we end up with 0.
Fetch the next digit (9) from the dividend, attach it to 0 and continue: 9 / 20

Moving on to step 6:
9 divided by 20 is 0 with a remainder of 9.
Record the quotient 0 as the next digit in the result. 
Result so far: 7990.0
Deduct 0 from 9 and we're left with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Moving on to step 7:
90 divided by 20 is 4 with a remainder of 10.
Put 4 as the next digit of the answer. 
Result so far: 7990.4
If we subtract 80 from 90, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Moving on to step 8:
100 divided by 20 is 5 with a remainder of 0.
Put 5 as the next digit of the answer. 
Result so far: 7990.45
Subtracting 100 from 100 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.

Step 9:
0 divided by 20 is 0 with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 7990.45
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 10:
When dividing 0 by 20, we get 0 with a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 7990.45
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.

The final result is 7990.45 with a remainder of 0.0.