We divide 851789 by 20
We're looking to find how many times 20 goes into 851789.

Going ahead to step 1:
8 divided by 20 is 0 with a remainder of 8.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 8 to get 8.
Grab the next digit (5) from the dividend, add it to 8, then carry on: 85 / 20

Moving on to step 2:
85 divided by 20 is 4 with a remainder of 5.
Write down 4 as next digit of the result. 
Result so far: 4.0
The remainder is 5 after subtracting 80 from 85.
Take the next digit (1) from the dividend and append it to 5, then repeat: 51 / 20

Advancing to step 3:
When dividing 51 by 20, we get 2 with a remainder of 11.
Put 2 as the next digit of the answer. 
Result so far: 42.0
The remainder is 11 after subtracting 40 from 51.
Fetch the next digit (7) from the dividend, attach it to 11 and continue: 117 / 20

Advancing to step 4:
If we divide 117 by 20, we get 5 and a remainder of 17.
Write down 5 as next digit of the result. 
Result so far: 425.0
If we subtract 100 from 117, we get 17.
Fetch the next digit (8) from the dividend, attach it to 17 and continue: 178 / 20

Going ahead to step 5:
20 goes into 178 8 times with a remainder of 18.
Write down 8 as next digit of the result. 
Result so far: 4258.0
Subtract 160 from 178 to get 18.
Take the next digit (9) from the dividend and append it to 18, then repeat: 189 / 20

Going ahead to step 6:
20 can be fit into 189 9 times, resulting in a remainder of 9.
The number 9 becomes the next digit in our result. 
Result so far: 42589.0
The remainder is 9 after subtracting 180 from 189.
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:
The number 20 fits into 90 4 times, leaving a remainder of 10.
The next digit of our result is 4. 
Result so far: 42589.4
The remainder is 10 after subtracting 80 from 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 8:
20 goes into 100 5 times with a remainder of 0.
Record the quotient 5 as the next digit in the result. 
Result so far: 42589.45
The remainder is 0 after subtracting 100 from 100.
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 9:
20 can be fit into 0 0 times, resulting in a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 42589.45
Subtract 0 from 0 to 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.

Moving on to step 10:
0 divided by 20 is 0 with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 42589.45
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.

Our division results in 42589.45 with a remaining 0.0.