We divide 453121 by 21
We want to divide 453121 by 21.

Let's proceed to step 1:
When dividing 4 by 21, we get 0 with a remainder of 4.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 4 after subtracting 0 from 4.
Bring next digit (5) of the dividend behind the 4 and repeat the process: 45 / 21

Advancing to step 2:
The number 21 fits into 45 2 times, leaving a remainder of 3.
Use 2 as the next digit of our solution. 
Result so far: 2.0
Subtracting 42 from 45 leaves us with 3.
Bring next digit (3) of the dividend behind the 3 and repeat the process: 33 / 21

Step 3:
33 divided by 21 is 1 with a remainder of 12.
Use 1 as the next digit of our solution. 
Result so far: 21.0
Subtracting 21 from 33 leaves us with 12.
Bring next digit (1) of the dividend behind the 12 and repeat the process: 121 / 21

Step 4:
The number 21 fits into 121 5 times, leaving a remainder of 16.
Use 5 as the next digit of our solution. 
Result so far: 215.0
The remainder is 16 after subtracting 105 from 121.
Take the next digit (2) from the dividend and append it to 16, then repeat: 162 / 21

Moving on to step 5:
If we divide 162 by 21, we get 7 and a remainder of 15.
Use 7 as the next digit of our solution. 
Result so far: 2157.0
Subtracting 147 from 162 leaves us with 15.
Grab the next digit (1) from the dividend, add it to 15, then carry on: 151 / 21

On to step 6:
If we divide 151 by 21, we get 7 and a remainder of 4.
The next digit of our result is 7. 
Result so far: 21577.0
If we take 147 away from 151, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 7:
The number 21 fits into 40 1 times, leaving a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 21577.1
If we take 21 away from 40, we end up with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Let's proceed to step 8:
190 divided by 21 is 9 with a remainder of 1.
Put 9 as the next digit of the answer. 
Result so far: 21577.19
Deduct 189 from 190 and we're left with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 9:
10 divided by 21 is 0 with a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 21577.19
If we subtract 0 from 10, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

On to step 10:
100 divided by 21 is 4 with a remainder of 16.
Put 4 as the next digit of the answer. 
Result so far: 21577.1904
If we take 84 away from 100, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

On to step 11:
160 divided by 21 is 7 with a remainder of 13.
The next digit of our result is 7. 
Result so far: 21577.19047
Deduct 147 from 160 and we're left with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Advancing to step 12:
21 goes into 130 6 times with a remainder of 4.
The next digit of our result is 6. 
Result so far: 21577.190476
Deduct 126 from 130 and we're left with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

On to step 13:
40 divided by 21 is 1 with a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 21577.1904761
Subtract 21 from 40 to get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Going ahead to step 14:
21 goes into 190 9 times with a remainder of 1.
Put 9 as the next digit of the answer. 
Result so far: 21577.19047619
If we subtract 189 from 190, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

The final outcome is 21577.19047619, with a leftover of 1e-09.