646660 ÷ 81 
Let's see how many times 81 fits into 646660.

On to step 1:
6 divided by 81 is 0 with a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Bring next digit (4) of the dividend behind the 6 and repeat the process: 64 / 81

Step 2:
The number 81 fits into 64 0 times, leaving a remainder of 64.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 64, we get 64.
Bring next digit (6) of the dividend behind the 64 and repeat the process: 646 / 81

Let's proceed to step 3:
The number 81 fits into 646 7 times, leaving a remainder of 79.
Record the quotient 7 as the next digit in the result. 
Result so far: 7.0
Deduct 567 from 646 and we're left with 79.
Grab the next digit (6) from the dividend, add it to 79, then carry on: 796 / 81

Let's proceed to step 4:
The number 81 fits into 796 9 times, leaving a remainder of 67.
Use 9 as the next digit of our solution. 
Result so far: 79.0
The remainder is 67 after subtracting 729 from 796.
Include the next digit (6) from the dividend after 67, then repeat: 676 / 81

Let's proceed to step 5:
When dividing 676 by 81, we get 8 with a remainder of 28.
The number 8 becomes the next digit in our result. 
Result so far: 798.0
If we subtract 648 from 676, we get 28.
Append the next digit (0) from the dividend to 28 and continue with: 280 / 81

Step 6:
When dividing 280 by 81, we get 3 with a remainder of 37.
Put 3 as the next digit of the answer. 
Result so far: 7983.0
Subtracting 243 from 280 leaves us with 37.
Since there are no more digits in the dividend, we add a zero to the remainder making it 370, and continue the process.

On to step 7:
The number 81 fits into 370 4 times, leaving a remainder of 46.
Write down 4 as next digit of the result. 
Result so far: 7983.4
Subtracting 324 from 370 leaves us with 46.
Since there are no more digits in the dividend, we add a zero to the remainder making it 460, and continue the process.

Going ahead to step 8:
When dividing 460 by 81, we get 5 with a remainder of 55.
The next digit of our result is 5. 
Result so far: 7983.45
If we take 405 away from 460, we end up with 55.
Since there are no more digits in the dividend, we add a zero to the remainder making it 550, and continue the process.

On to step 9:
81 can be fit into 550 6 times, resulting in a remainder of 64.
The next digit of our result is 6. 
Result so far: 7983.456
If we take 486 away from 550, we end up with 64.
Since there are no more digits in the dividend, we add a zero to the remainder making it 640, and continue the process.

Advancing to step 10:
640 divided by 81 is 7 with a remainder of 73.
Write down 7 as next digit of the result. 
Result so far: 7983.4567
If we take 567 away from 640, we end up with 73.
Since there are no more digits in the dividend, we add a zero to the remainder making it 730, and continue the process.

Moving on to step 11:
The number 81 fits into 730 9 times, leaving a remainder of 1.
Put 9 as the next digit of the answer. 
Result so far: 7983.45679
Subtract 729 from 730 to get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 12:
10 divided by 81 is 0 with a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 7983.45679
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.

Step 13:
If we divide 100 by 81, we get 1 and a remainder of 19.
Put 1 as the next digit of the answer. 
Result so far: 7983.4567901
Deduct 81 from 100 and we're left 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.

On to step 14:
190 divided by 81 is 2 with a remainder of 28.
The number 2 becomes the next digit in our result. 
Result so far: 7983.45679012
Deduct 162 from 190 and we're left with 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

The final outcome is 7983.45679012, with a leftover of 2.8e-08.