399410 ÷ 81 
Our goal is to divide 399410 by 81.

Advancing to step 1:
3 divided by 81 is 0 with a remainder of 3.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 3, we end up with 3.
Grab the next digit (9) from the dividend, add it to 3, then carry on: 39 / 81

Advancing to step 2:
81 goes into 39 0 times with a remainder of 39.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 39 and we're left with 39.
Grab the next digit (9) from the dividend, add it to 39, then carry on: 399 / 81

Going ahead to step 3:
81 can be fit into 399 4 times, resulting in a remainder of 75.
Put 4 as the next digit of the answer. 
Result so far: 4.0
Subtracting 324 from 399 leaves us with 75.
Grab the next digit (4) from the dividend, add it to 75, then carry on: 754 / 81

Step 4:
If we divide 754 by 81, we get 9 and a remainder of 25.
Record the quotient 9 as the next digit in the result. 
Result so far: 49.0
The remainder is 25 after subtracting 729 from 754.
Take the next digit (1) from the dividend and append it to 25, then repeat: 251 / 81

Advancing to step 5:
If we divide 251 by 81, we get 3 and a remainder of 8.
Write down 3 as next digit of the result. 
Result so far: 493.0
Subtract 243 from 251 to get 8.
Include the next digit (0) from the dividend after 8, then repeat: 80 / 81

Advancing to step 6:
If we divide 80 by 81, we get 0 and a remainder of 80.
The number 0 becomes the next digit in our result. 
Result so far: 4930.0
If we take 0 away from 80, we end up with 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 800, and continue the process.

Going ahead to step 7:
81 goes into 800 9 times with a remainder of 71.
Put 9 as the next digit of the answer. 
Result so far: 4930.9
Deduct 729 from 800 and we're left with 71.
Since there are no more digits in the dividend, we add a zero to the remainder making it 710, and continue the process.

Advancing to step 8:
The number 81 fits into 710 8 times, leaving a remainder of 62.
Put 8 as the next digit of the answer. 
Result so far: 4930.98
The remainder is 62 after subtracting 648 from 710.
Since there are no more digits in the dividend, we add a zero to the remainder making it 620, and continue the process.

Let's proceed to step 9:
When dividing 620 by 81, we get 7 with a remainder of 53.
The next digit of our result is 7. 
Result so far: 4930.987
If we subtract 567 from 620, we get 53.
Since there are no more digits in the dividend, we add a zero to the remainder making it 530, and continue the process.

Going ahead to step 10:
The number 81 fits into 530 6 times, leaving a remainder of 44.
Write down 6 as next digit of the result. 
Result so far: 4930.9876
Subtract 486 from 530 to get 44.
Since there are no more digits in the dividend, we add a zero to the remainder making it 440, and continue the process.

Moving on to step 11:
When dividing 440 by 81, we get 5 with a remainder of 35.
The next digit of our result is 5. 
Result so far: 4930.98765
Deduct 405 from 440 and we're left with 35.
Since there are no more digits in the dividend, we add a zero to the remainder making it 350, and continue the process.

On to step 12:
81 goes into 350 4 times with a remainder of 26.
Use 4 as the next digit of our solution. 
Result so far: 4930.987654
The remainder is 26 after subtracting 324 from 350.
Since there are no more digits in the dividend, we add a zero to the remainder making it 260, and continue the process.

Going ahead to step 13:
81 goes into 260 3 times with a remainder of 17.
Record the quotient 3 as the next digit in the result. 
Result so far: 4930.9876543
Deduct 243 from 260 and we're left with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Moving on to step 14:
81 goes into 170 2 times with a remainder of 8.
The next digit of our result is 2. 
Result so far: 4930.98765432
If we take 162 away from 170, 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.

The final outcome is 4930.98765432, with a leftover of 8e-09.