Let's divide 643338 by 20
We're looking to find how many times 20 goes into 643338.

Step 1:
20 goes into 6 0 times with a remainder of 6.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Grab the next digit (4) from the dividend, add it to 6, then carry on: 64 / 20

On to step 2:
If we divide 64 by 20, we get 3 and a remainder of 4.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
If we take 60 away from 64, we end up with 4.
Grab the next digit (3) from the dividend, add it to 4, then carry on: 43 / 20

On to step 3:
20 goes into 43 2 times with a remainder of 3.
The number 2 becomes the next digit in our result. 
Result so far: 32.0
Subtracting 40 from 43 leaves us with 3.
Grab the next digit (3) from the dividend, add it to 3, then carry on: 33 / 20

Let's proceed to step 4:
20 can be fit into 33 1 times, resulting in a remainder of 13.
Write down 1 as next digit of the result. 
Result so far: 321.0
Deduct 20 from 33 and we're left with 13.
Take the next digit (3) from the dividend and append it to 13, then repeat: 133 / 20

On to step 5:
The number 20 fits into 133 6 times, leaving a remainder of 13.
The next digit of our result is 6. 
Result so far: 3216.0
Deduct 120 from 133 and we're left with 13.
Grab the next digit (8) from the dividend, add it to 13, then carry on: 138 / 20

On to step 6:
138 divided by 20 is 6 with a remainder of 18.
The next digit of our result is 6. 
Result so far: 32166.0
If we subtract 120 from 138, we get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Moving on to step 7:
The number 20 fits into 180 9 times, leaving a remainder of 0.
Write down 9 as next digit of the result. 
Result so far: 32166.9
Deduct 180 from 180 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.

Going ahead to step 8:
The number 20 fits into 0 0 times, leaving a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 32166.9
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.

Going ahead to step 9:
20 can be fit into 0 0 times, resulting in a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 32166.9
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.

The final outcome is 32166.9, with a leftover of 0.0.