8510728 ÷ 405 
We want to figure out the number of times 8510728 can be divided by 405.

On to step 1:
8 divided by 405 is 0 with a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 8, we end up with 8.
Include the next digit (5) from the dividend after 8, then repeat: 85 / 405

On to step 2:
405 goes into 85 0 times with a remainder of 85.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 85, we get 85.
Take the next digit (1) from the dividend and append it to 85, then repeat: 851 / 405

Going ahead to step 3:
405 goes into 851 2 times with a remainder of 41.
Put 2 as the next digit of the answer. 
Result so far: 2.0
Subtracting 810 from 851 leaves us with 41.
Bring next digit (0) of the dividend behind the 41 and repeat the process: 410 / 405

On to step 4:
When dividing 410 by 405, we get 1 with a remainder of 5.
Use 1 as the next digit of our solution. 
Result so far: 21.0
The remainder is 5 after subtracting 405 from 410.
Fetch the next digit (7) from the dividend, attach it to 5 and continue: 57 / 405

Going ahead to step 5:
If we divide 57 by 405, we get 0 and a remainder of 57.
Write down 0 as next digit of the result. 
Result so far: 210.0
Subtract 0 from 57 to get 57.
Take the next digit (2) from the dividend and append it to 57, then repeat: 572 / 405

Going ahead to step 6:
572 divided by 405 is 1 with a remainder of 167.
The number 1 becomes the next digit in our result. 
Result so far: 2101.0
Deduct 405 from 572 and we're left with 167.
Bring next digit (8) of the dividend behind the 167 and repeat the process: 1678 / 405

Step 7:
405 can be fit into 1678 4 times, resulting in a remainder of 58.
The next digit of our result is 4. 
Result so far: 21014.0
The remainder is 58 after subtracting 1620 from 1678.
Since there are no more digits in the dividend, we add a zero to the remainder making it 580, and continue the process.

Let's proceed to step 8:
405 goes into 580 1 times with a remainder of 175.
Record the quotient 1 as the next digit in the result. 
Result so far: 21014.1
Subtracting 405 from 580 leaves us with 175.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1750, and continue the process.

Advancing to step 9:
1750 divided by 405 is 4 with a remainder of 130.
The next digit of our result is 4. 
Result so far: 21014.14
The remainder is 130 after subtracting 1620 from 1750.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1300, and continue the process.

Moving on to step 10:
The number 405 fits into 1300 3 times, leaving a remainder of 85.
Record the quotient 3 as the next digit in the result. 
Result so far: 21014.143
Subtracting 1215 from 1300 leaves us with 85.
Since there are no more digits in the dividend, we add a zero to the remainder making it 850, and continue the process.

On to step 11:
The number 405 fits into 850 2 times, leaving a remainder of 40.
The number 2 becomes the next digit in our result. 
Result so far: 21014.1432
The remainder is 40 after subtracting 810 from 850.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Moving on to step 12:
The number 405 fits into 400 0 times, leaving a remainder of 400.
The next digit of our result is 0. 
Result so far: 21014.1432
If we subtract 0 from 400, we get 400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4000, and continue the process.

On to step 13:
When dividing 4000 by 405, we get 9 with a remainder of 355.
Record the quotient 9 as the next digit in the result. 
Result so far: 21014.143209
Subtract 3645 from 4000 to get 355.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3550, and continue the process.

Moving on to step 14:
The number 405 fits into 3550 8 times, leaving a remainder of 310.
Use 8 as the next digit of our solution. 
Result so far: 21014.1432098
If we subtract 3240 from 3550, we get 310.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3100, and continue the process.

Moving on to step 15:
3100 divided by 405 is 7 with a remainder of 265.
The next digit of our result is 7. 
Result so far: 21014.14320987
Deduct 2835 from 3100 and we're left with 265.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2650, and continue the process.

The final result is 21014.14320987 with a remainder of 2.65e-07.