31310286 ÷ 399 
We want to divide 31310286 by 399.

Let's proceed to step 1:
399 goes into 3 0 times with a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 3, we end up with 3.
Append the next digit (1) from the dividend to 3 and continue with: 31 / 399

Advancing to step 2:
If we divide 31 by 399, we get 0 and a remainder of 31.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 31 leaves us with 31.
Include the next digit (3) from the dividend after 31, then repeat: 313 / 399

On to step 3:
313 divided by 399 is 0 with a remainder of 313.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 313 and we're left with 313.
Include the next digit (1) from the dividend after 313, then repeat: 3131 / 399

Advancing to step 4:
399 can be fit into 3131 7 times, resulting in a remainder of 338.
Record the quotient 7 as the next digit in the result. 
Result so far: 7.0
Deduct 2793 from 3131 and we're left with 338.
Fetch the next digit (0) from the dividend, attach it to 338 and continue: 3380 / 399

Going ahead to step 5:
3380 divided by 399 is 8 with a remainder of 188.
The number 8 becomes the next digit in our result. 
Result so far: 78.0
Subtract 3192 from 3380 to get 188.
Take the next digit (2) from the dividend and append it to 188, then repeat: 1882 / 399

Step 6:
1882 divided by 399 is 4 with a remainder of 286.
The number 4 becomes the next digit in our result. 
Result so far: 784.0
The remainder is 286 after subtracting 1596 from 1882.
Take the next digit (8) from the dividend and append it to 286, then repeat: 2868 / 399

Going ahead to step 7:
399 can be fit into 2868 7 times, resulting in a remainder of 75.
Put 7 as the next digit of the answer. 
Result so far: 7847.0
If we subtract 2793 from 2868, we get 75.
Grab the next digit (6) from the dividend, add it to 75, then carry on: 756 / 399

On to step 8:
399 goes into 756 1 times with a remainder of 357.
The next digit of our result is 1. 
Result so far: 78471.0
Subtracting 399 from 756 leaves us with 357.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3570, and continue the process.

Advancing to step 9:
If we divide 3570 by 399, we get 8 and a remainder of 378.
Put 8 as the next digit of the answer. 
Result so far: 78471.8
If we subtract 3192 from 3570, we get 378.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3780, and continue the process.

Step 10:
3780 divided by 399 is 9 with a remainder of 189.
Record the quotient 9 as the next digit in the result. 
Result so far: 78471.89
Subtract 3591 from 3780 to get 189.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1890, and continue the process.

Going ahead to step 11:
399 goes into 1890 4 times with a remainder of 294.
Use 4 as the next digit of our solution. 
Result so far: 78471.894
Deduct 1596 from 1890 and we're left with 294.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2940, and continue the process.

Let's proceed to step 12:
If we divide 2940 by 399, we get 7 and a remainder of 147.
Put 7 as the next digit of the answer. 
Result so far: 78471.8947
If we take 2793 away from 2940, we end up with 147.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1470, and continue the process.

Moving on to step 13:
1470 divided by 399 is 3 with a remainder of 273.
Write down 3 as next digit of the result. 
Result so far: 78471.89473
Subtract 1197 from 1470 to get 273.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2730, and continue the process.

Going ahead to step 14:
When dividing 2730 by 399, we get 6 with a remainder of 336.
Put 6 as the next digit of the answer. 
Result so far: 78471.894736
Subtracting 2394 from 2730 leaves us with 336.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3360, and continue the process.

Let's proceed to step 15:
When dividing 3360 by 399, we get 8 with a remainder of 168.
Record the quotient 8 as the next digit in the result. 
Result so far: 78471.8947368
The remainder is 168 after subtracting 3192 from 3360.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1680, and continue the process.

On to step 16:
399 can be fit into 1680 4 times, resulting in a remainder of 84.
Use 4 as the next digit of our solution. 
Result so far: 78471.89473684
The remainder is 84 after subtracting 1596 from 1680.
Since there are no more digits in the dividend, we add a zero to the remainder making it 840, and continue the process.

In conclusion, the division gives 78471.89473684 with a balance of 8.4e-08.