644839 divided by 81 
We want to divide 644839 by 81.

Going ahead to step 1:
81 can be fit into 6 0 times, resulting in a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Include the next digit (4) from the dividend after 6, then repeat: 64 / 81

Moving on to step 2:
If we divide 64 by 81, we get 0 and a remainder of 64.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 64, we end up with 64.
Append the next digit (4) from the dividend to 64 and continue with: 644 / 81

Advancing to step 3:
If we divide 644 by 81, we get 7 and a remainder of 77.
Record the quotient 7 as the next digit in the result. 
Result so far: 7.0
If we subtract 567 from 644, we get 77.
Bring next digit (8) of the dividend behind the 77 and repeat the process: 778 / 81

Moving on to step 4:
81 goes into 778 9 times with a remainder of 49.
The number 9 becomes the next digit in our result. 
Result so far: 79.0
Subtract 729 from 778 to get 49.
Grab the next digit (3) from the dividend, add it to 49, then carry on: 493 / 81

Going ahead to step 5:
The number 81 fits into 493 6 times, leaving a remainder of 7.
Put 6 as the next digit of the answer. 
Result so far: 796.0
Deduct 486 from 493 and we're left with 7.
Bring next digit (9) of the dividend behind the 7 and repeat the process: 79 / 81

Moving on to step 6:
The number 81 fits into 79 0 times, leaving a remainder of 79.
Use 0 as the next digit of our solution. 
Result so far: 7960.0
If we subtract 0 from 79, we get 79.
Since there are no more digits in the dividend, we add a zero to the remainder making it 790, and continue the process.

On to step 7:
The number 81 fits into 790 9 times, leaving a remainder of 61.
The next digit of our result is 9. 
Result so far: 7960.9
If we subtract 729 from 790, we get 61.
Since there are no more digits in the dividend, we add a zero to the remainder making it 610, and continue the process.

Step 8:
When dividing 610 by 81, we get 7 with a remainder of 43.
The number 7 becomes the next digit in our result. 
Result so far: 7960.97
If we take 567 away from 610, we end up with 43.
Since there are no more digits in the dividend, we add a zero to the remainder making it 430, and continue the process.

Advancing to step 9:
If we divide 430 by 81, we get 5 and a remainder of 25.
Write down 5 as next digit of the result. 
Result so far: 7960.975
Subtracting 405 from 430 leaves us with 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

On to step 10:
If we divide 250 by 81, we get 3 and a remainder of 7.
Write down 3 as next digit of the result. 
Result so far: 7960.9753
Deduct 243 from 250 and we're left with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Step 11:
81 goes into 70 0 times with a remainder of 70.
Record the quotient 0 as the next digit in the result. 
Result so far: 7960.9753
Subtracting 0 from 70 leaves us with 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Let's proceed to step 12:
81 goes into 700 8 times with a remainder of 52.
Use 8 as the next digit of our solution. 
Result so far: 7960.975308
The remainder is 52 after subtracting 648 from 700.
Since there are no more digits in the dividend, we add a zero to the remainder making it 520, and continue the process.

Advancing to step 13:
The number 81 fits into 520 6 times, leaving a remainder of 34.
Record the quotient 6 as the next digit in the result. 
Result so far: 7960.9753086
Subtract 486 from 520 to get 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

Advancing to step 14:
81 can be fit into 340 4 times, resulting in a remainder of 16.
The next digit of our result is 4. 
Result so far: 7960.97530864
If we take 324 away from 340, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

In conclusion, the division gives 7960.97530864 with a balance of 1.6e-08.