We look at the division of 240397 by 21 
We're looking to find how many times 21 goes into 240397.

Moving on to step 1:
The number 21 fits into 2 0 times, leaving a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 2, we get 2.
Take the next digit (4) from the dividend and append it to 2, then repeat: 24 / 21

Moving on to step 2:
When dividing 24 by 21, we get 1 with a remainder of 3.
Write down 1 as next digit of the result. 
Result so far: 1.0
The remainder is 3 after subtracting 21 from 24.
Bring next digit (0) of the dividend behind the 3 and repeat the process: 30 / 21

Let's proceed 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: 11.0
Deduct 21 from 30 and we're left with 9.
Fetch the next digit (3) from the dividend, attach it to 9 and continue: 93 / 21

On to step 4:
93 divided by 21 is 4 with a remainder of 9.
Record the quotient 4 as the next digit in the result. 
Result so far: 114.0
Subtract 84 from 93 to get 9.
Bring next digit (9) of the dividend behind the 9 and repeat the process: 99 / 21

On to step 5:
The number 21 fits into 99 4 times, leaving a remainder of 15.
Record the quotient 4 as the next digit in the result. 
Result so far: 1144.0
Subtract 84 from 99 to get 15.
Append the next digit (7) from the dividend to 15 and continue with: 157 / 21

Step 6:
The number 21 fits into 157 7 times, leaving a remainder of 10.
The next digit of our result is 7. 
Result so far: 11447.0
Deduct 147 from 157 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 7:
If we divide 100 by 21, we get 4 and a remainder of 16.
The next digit of our result is 4. 
Result so far: 11447.4
Deduct 84 from 100 and we're left 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.

Step 8:
21 goes into 160 7 times with a remainder of 13.
Write down 7 as next digit of the result. 
Result so far: 11447.47
Subtracting 147 from 160 leaves us 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 9:
When dividing 130 by 21, we get 6 with a remainder of 4.
Put 6 as the next digit of the answer. 
Result so far: 11447.476
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.

Step 10:
If we divide 40 by 21, we get 1 and a remainder of 19.
Put 1 as the next digit of the answer. 
Result so far: 11447.4761
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.

Moving on to step 11:
The number 21 fits into 190 9 times, leaving a remainder of 1.
The next digit of our result is 9. 
Result so far: 11447.47619
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.

Let's proceed to step 12:
10 divided by 21 is 0 with a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 11447.47619
If we take 0 away from 10, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 13:
21 can be fit into 100 4 times, resulting in a remainder of 16.
Record the quotient 4 as the next digit in the result. 
Result so far: 11447.4761904
If we subtract 84 from 100, we get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Going ahead to step 14:
160 divided by 21 is 7 with a remainder of 13.
Use 7 as the next digit of our solution. 
Result so far: 11447.47619047
Subtracting 147 from 160 leaves us 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.

The final outcome is 11447.47619047, with a leftover of 1.3e-08.