We look at the division of 450180 by 21 
Our goal is to divide 450180 by 21.

Moving on to step 1:
21 can be fit into 4 0 times, resulting in a remainder of 4.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 4 to get 4.
Bring next digit (5) of the dividend behind the 4 and repeat the process: 45 / 21

On to step 2:
The number 21 fits into 45 2 times, leaving a remainder of 3.
Put 2 as the next digit of the answer. 
Result so far: 2.0
Deduct 42 from 45 and we're left with 3.
Include the next digit (0) from the dividend after 3, then repeat: 30 / 21

Advancing to step 3:
When dividing 30 by 21, we get 1 with a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 21.0
Subtract 21 from 30 to get 9.
Fetch the next digit (1) from the dividend, attach it to 9 and continue: 91 / 21

Moving on to step 4:
When dividing 91 by 21, we get 4 with a remainder of 7.
Record the quotient 4 as the next digit in the result. 
Result so far: 214.0
Subtract 84 from 91 to get 7.
Fetch the next digit (8) from the dividend, attach it to 7 and continue: 78 / 21

Moving on to step 5:
21 goes into 78 3 times with a remainder of 15.
Put 3 as the next digit of the answer. 
Result so far: 2143.0
If we subtract 63 from 78, we get 15.
Bring next digit (0) of the dividend behind the 15 and repeat the process: 150 / 21

Step 6:
150 divided by 21 is 7 with a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 21437.0
If we subtract 147 from 150, we get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 7:
21 goes into 30 1 times with a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 21437.1
The remainder is 9 after subtracting 21 from 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Moving on to step 8:
21 can be fit into 90 4 times, resulting in a remainder of 6.
The next digit of our result is 4. 
Result so far: 21437.14
If we subtract 84 from 90, we get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Going ahead to step 9:
The number 21 fits into 60 2 times, leaving a remainder of 18.
Record the quotient 2 as the next digit in the result. 
Result so far: 21437.142
If we subtract 42 from 60, 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 10:
If we divide 180 by 21, we get 8 and a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 21437.1428
The remainder is 12 after subtracting 168 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Let's proceed to step 11:
21 can be fit into 120 5 times, resulting in a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 21437.14285
Subtract 105 from 120 to get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Let's proceed to step 12:
21 can be fit into 150 7 times, resulting in a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 21437.142857
Deduct 147 from 150 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Let's proceed to step 13:
21 can be fit into 30 1 times, resulting in a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 21437.1428571
The remainder is 9 after subtracting 21 from 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Advancing to step 14:
21 can be fit into 90 4 times, resulting in a remainder of 6.
Use 4 as the next digit of our solution. 
Result so far: 21437.14285714
The remainder is 6 after subtracting 84 from 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

The final result is 21437.14285714 with a remainder of 6e-09.