We're dividing 399405 by 23 
We want to divide 399405 by 23.

Going ahead to step 1:
When dividing 3 by 23, we get 0 with a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Bring next digit (9) of the dividend behind the 3 and repeat the process: 39 / 23

Step 2:
23 can be fit into 39 1 times, resulting in a remainder of 16.
Put 1 as the next digit of the answer. 
Result so far: 1.0
If we subtract 23 from 39, we get 16.
Fetch the next digit (9) from the dividend, attach it to 16 and continue: 169 / 23

Step 3:
169 divided by 23 is 7 with a remainder of 8.
Write down 7 as next digit of the result. 
Result so far: 17.0
Subtract 161 from 169 to get 8.
Include the next digit (4) from the dividend after 8, then repeat: 84 / 23

On to step 4:
The number 23 fits into 84 3 times, leaving a remainder of 15.
Record the quotient 3 as the next digit in the result. 
Result so far: 173.0
Subtracting 69 from 84 leaves us with 15.
Fetch the next digit (0) from the dividend, attach it to 15 and continue: 150 / 23

Going ahead to step 5:
When dividing 150 by 23, we get 6 with a remainder of 12.
Record the quotient 6 as the next digit in the result. 
Result so far: 1736.0
The remainder is 12 after subtracting 138 from 150.
Take the next digit (5) from the dividend and append it to 12, then repeat: 125 / 23

Moving on to step 6:
23 goes into 125 5 times with a remainder of 10.
Use 5 as the next digit of our solution. 
Result so far: 17365.0
Subtract 115 from 125 to 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.

Going ahead to step 7:
23 goes into 100 4 times with a remainder of 8.
Write down 4 as next digit of the result. 
Result so far: 17365.4
If we take 92 away from 100, 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.

Going ahead to step 8:
When dividing 80 by 23, we get 3 with a remainder of 11.
Record the quotient 3 as the next digit in the result. 
Result so far: 17365.43
Deduct 69 from 80 and we're left 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 9:
When dividing 110 by 23, we get 4 with a remainder of 18.
The number 4 becomes the next digit in our result. 
Result so far: 17365.434
The remainder is 18 after subtracting 92 from 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

On to step 10:
If we divide 180 by 23, we get 7 and a remainder of 19.
Use 7 as the next digit of our solution. 
Result so far: 17365.4347
If we take 161 away from 180, 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.

Going ahead to step 11:
23 can be fit into 190 8 times, resulting in a remainder of 6.
The next digit of our result is 8. 
Result so far: 17365.43478
If we take 184 away from 190, we end up with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 12:
23 can be fit into 60 2 times, resulting in a remainder of 14.
Put 2 as the next digit of the answer. 
Result so far: 17365.434782
If we subtract 46 from 60, we get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Step 13:
If we divide 140 by 23, we get 6 and a remainder of 2.
The number 6 becomes the next digit in our result. 
Result so far: 17365.4347826
If we take 138 away from 140, we end up 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 14:
23 goes into 20 0 times with a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 17365.4347826
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.

Our division results in 17365.4347826 with a remaining 2e-08.