Let's divide 431870 by 21
Our goal is to divide 431870 by 21.

Moving on to step 1:
If we divide 4 by 21, we get 0 and a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 4 after subtracting 0 from 4.
Fetch the next digit (3) from the dividend, attach it to 4 and continue: 43 / 21

Step 2:
21 goes into 43 2 times with a remainder of 1.
The next digit of our result is 2. 
Result so far: 2.0
The remainder is 1 after subtracting 42 from 43.
Fetch the next digit (1) from the dividend, attach it to 1 and continue: 11 / 21

On to step 3:
21 can be fit into 11 0 times, resulting in a remainder of 11.
Record the quotient 0 as the next digit in the result. 
Result so far: 20.0
Subtracting 0 from 11 leaves us with 11.
Append the next digit (8) from the dividend to 11 and continue with: 118 / 21

Moving on to step 4:
When dividing 118 by 21, we get 5 with a remainder of 13.
The next digit of our result is 5. 
Result so far: 205.0
The remainder is 13 after subtracting 105 from 118.
Take the next digit (7) from the dividend and append it to 13, then repeat: 137 / 21

Step 5:
The number 21 fits into 137 6 times, leaving a remainder of 11.
The next digit of our result is 6. 
Result so far: 2056.0
If we subtract 126 from 137, we get 11.
Include the next digit (0) from the dividend after 11, then repeat: 110 / 21

Going ahead to step 6:
If we divide 110 by 21, we get 5 and a remainder of 5.
Write down 5 as next digit of the result. 
Result so far: 20565.0
Subtracting 105 from 110 leaves us with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Advancing to step 7:
21 goes into 50 2 times with a remainder of 8.
The number 2 becomes the next digit in our result. 
Result so far: 20565.2
If we take 42 away from 50, we end up with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 8:
21 goes into 80 3 times with a remainder of 17.
Use 3 as the next digit of our solution. 
Result so far: 20565.23
If we subtract 63 from 80, we get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Advancing to step 9:
21 goes into 170 8 times with a remainder of 2.
The next digit of our result is 8. 
Result so far: 20565.238
Subtracting 168 from 170 leaves us with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Moving on to step 10:
If we divide 20 by 21, we get 0 and a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 20565.238
Subtracting 0 from 20 leaves us with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Advancing to step 11:
When dividing 200 by 21, we get 9 with a remainder of 11.
The number 9 becomes the next digit in our result. 
Result so far: 20565.23809
Subtract 189 from 200 to get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

On to step 12:
21 can be fit into 110 5 times, resulting in a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 20565.238095
If we subtract 105 from 110, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Let's proceed to step 13:
50 divided by 21 is 2 with a remainder of 8.
The number 2 becomes the next digit in our result. 
Result so far: 20565.2380952
The remainder is 8 after subtracting 42 from 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Advancing to step 14:
21 goes into 80 3 times with a remainder of 17.
Use 3 as the next digit of our solution. 
Result so far: 20565.23809523
If we subtract 63 from 80, we get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Our division results in 20565.23809523 with a remaining 1.7e-08.