We divide 421010 by 20
Let's see how many times 20 fits into 421010.

Going ahead to step 1:
The number 20 fits into 4 0 times, leaving a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 4 and we're left with 4.
Append the next digit (2) from the dividend to 4 and continue with: 42 / 20

Going ahead to step 2:
The number 20 fits into 42 2 times, leaving a remainder of 2.
Put 2 as the next digit of the answer. 
Result so far: 2.0
Deduct 40 from 42 and we're left with 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 20

Let's proceed to step 3:
The number 20 fits into 21 1 times, leaving a remainder of 1.
The next digit of our result is 1. 
Result so far: 21.0
If we take 20 away from 21, we end up with 1.
Bring next digit (0) of the dividend behind the 1 and repeat the process: 10 / 20

On to step 4:
If we divide 10 by 20, we get 0 and a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 210.0
Subtract 0 from 10 to get 10.
Append the next digit (1) from the dividend to 10 and continue with: 101 / 20

Step 5:
101 divided by 20 is 5 with a remainder of 1.
Put 5 as the next digit of the answer. 
Result so far: 2105.0
If we take 100 away from 101, we end up with 1.
Grab the next digit (0) from the dividend, add it to 1, then carry on: 10 / 20

Moving on to step 6:
If we divide 10 by 20, we get 0 and a remainder of 10.
The next digit of our result is 0. 
Result so far: 21050.0
Subtracting 0 from 10 leaves us with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 7:
20 goes into 100 5 times with a remainder of 0.
Use 5 as the next digit of our solution. 
Result so far: 21050.5
If we subtract 100 from 100, 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.

On to step 8:
When dividing 0 by 20, we get 0 with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 21050.5
The remainder is 0 after subtracting 0 from 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:
When dividing 0 by 20, we get 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 21050.5
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.

The final outcome is 21050.5, with a leftover of 0.0.