We look at the division of 436712 by 21 
We want to figure out the number of times 436712 can be divided by 21.

Advancing to step 1:
21 goes into 4 0 times with a remainder of 4.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 4, we get 4.
Fetch the next digit (3) from the dividend, attach it to 4 and continue: 43 / 21

Going ahead to step 2:
If we divide 43 by 21, we get 2 and a remainder of 1.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
If we take 42 away from 43, we end up with 1.
Append the next digit (6) from the dividend to 1 and continue with: 16 / 21

On to step 3:
21 can be fit into 16 0 times, resulting in a remainder of 16.
The next digit of our result is 0. 
Result so far: 20.0
Subtracting 0 from 16 leaves us with 16.
Append the next digit (7) from the dividend to 16 and continue with: 167 / 21

Step 4:
When dividing 167 by 21, we get 7 with a remainder of 20.
The number 7 becomes the next digit in our result. 
Result so far: 207.0
The remainder is 20 after subtracting 147 from 167.
Grab the next digit (1) from the dividend, add it to 20, then carry on: 201 / 21

Let's proceed to step 5:
201 divided by 21 is 9 with a remainder of 12.
The number 9 becomes the next digit in our result. 
Result so far: 2079.0
The remainder is 12 after subtracting 189 from 201.
Take the next digit (2) from the dividend and append it to 12, then repeat: 122 / 21

Step 6:
21 goes into 122 5 times with a remainder of 17.
Record the quotient 5 as the next digit in the result. 
Result so far: 20795.0
If we subtract 105 from 122, 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.

Step 7:
21 goes into 170 8 times with a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 20795.8
The remainder is 2 after subtracting 168 from 170.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

On to step 8:
21 can be fit into 20 0 times, resulting in a remainder of 20.
Record the quotient 0 as the next digit in the result. 
Result so far: 20795.8
If we subtract 0 from 20, we get 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 9:
21 goes into 200 9 times with a remainder of 11.
Record the quotient 9 as the next digit in the result. 
Result so far: 20795.809
If we take 189 away from 200, we end up with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Moving on to step 10:
When dividing 110 by 21, we get 5 with a remainder of 5.
Use 5 as the next digit of our solution. 
Result so far: 20795.8095
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.

Advancing to step 11:
If we divide 50 by 21, we get 2 and a remainder of 8.
Use 2 as the next digit of our solution. 
Result so far: 20795.80952
Subtract 42 from 50 to get 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 12:
21 goes into 80 3 times with a remainder of 17.
Put 3 as the next digit of the answer. 
Result so far: 20795.809523
The remainder is 17 after subtracting 63 from 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Step 13:
When dividing 170 by 21, we get 8 with a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 20795.8095238
Subtract 168 from 170 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

On to step 14:
20 divided by 21 is 0 with a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 20795.8095238
If we subtract 0 from 20, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

The final outcome is 20795.8095238, with a leftover of 2e-08.