Let's divide 878840 by 20
We want to divide 878840 by 20.

Step 1:
The number 20 fits into 8 0 times, leaving a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 8 after subtracting 0 from 8.
Append the next digit (7) from the dividend to 8 and continue with: 87 / 20

Step 2:
When dividing 87 by 20, we get 4 with a remainder of 7.
Put 4 as the next digit of the answer. 
Result so far: 4.0
Subtract 80 from 87 to get 7.
Append the next digit (8) from the dividend to 7 and continue with: 78 / 20

On to step 3:
20 can be fit into 78 3 times, resulting in a remainder of 18.
The number 3 becomes the next digit in our result. 
Result so far: 43.0
The remainder is 18 after subtracting 60 from 78.
Bring next digit (8) of the dividend behind the 18 and repeat the process: 188 / 20

On to step 4:
20 can be fit into 188 9 times, resulting in a remainder of 8.
The next digit of our result is 9. 
Result so far: 439.0
If we subtract 180 from 188, we get 8.
Fetch the next digit (4) from the dividend, attach it to 8 and continue: 84 / 20

Step 5:
20 goes into 84 4 times with a remainder of 4.
Write down 4 as next digit of the result. 
Result so far: 4394.0
If we take 80 away from 84, we end up with 4.
Fetch the next digit (0) from the dividend, attach it to 4 and continue: 40 / 20

Advancing to step 6:
When dividing 40 by 20, we get 2 with a remainder of 0.
Record the quotient 2 as the next digit in the result. 
Result so far: 43942.0
Deduct 40 from 40 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.

Advancing to step 7:
20 can be fit into 0 0 times, resulting in a remainder of 0.
The next digit of our result is 0. 
Result so far: 43942.0
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 8:
20 can be fit into 0 0 times, resulting in a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 43942.0
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 outcome is 43942.0, with a leftover of 0.0.