81578728 divided by 646 
We want to figure out the number of times 81578728 can be divided by 646.

Moving on to step 1:
If we divide 8 by 646, we get 0 and a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Grab the next digit (1) from the dividend, add it to 8, then carry on: 81 / 646

On to step 2:
646 goes into 81 0 times with a remainder of 81.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 81, we end up with 81.
Take the next digit (5) from the dividend and append it to 81, then repeat: 815 / 646

Moving on to step 3:
646 can be fit into 815 1 times, resulting in a remainder of 169.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we take 646 away from 815, we end up with 169.
Bring next digit (7) of the dividend behind the 169 and repeat the process: 1697 / 646

Advancing to step 4:
When dividing 1697 by 646, we get 2 with a remainder of 405.
Put 2 as the next digit of the answer. 
Result so far: 12.0
Deduct 1292 from 1697 and we're left with 405.
Append the next digit (8) from the dividend to 405 and continue with: 4058 / 646

Advancing to step 5:
The number 646 fits into 4058 6 times, leaving a remainder of 182.
The number 6 becomes the next digit in our result. 
Result so far: 126.0
Subtract 3876 from 4058 to get 182.
Fetch the next digit (7) from the dividend, attach it to 182 and continue: 1827 / 646

Advancing to step 6:
1827 divided by 646 is 2 with a remainder of 535.
The next digit of our result is 2. 
Result so far: 1262.0
Subtracting 1292 from 1827 leaves us with 535.
Append the next digit (2) from the dividend to 535 and continue with: 5352 / 646

Moving on to step 7:
5352 divided by 646 is 8 with a remainder of 184.
Write down 8 as next digit of the result. 
Result so far: 12628.0
If we take 5168 away from 5352, we end up with 184.
Bring next digit (8) of the dividend behind the 184 and repeat the process: 1848 / 646

On to step 8:
If we divide 1848 by 646, we get 2 and a remainder of 556.
The next digit of our result is 2. 
Result so far: 126282.0
Subtracting 1292 from 1848 leaves us with 556.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5560, and continue the process.

Advancing to step 9:
5560 divided by 646 is 8 with a remainder of 392.
Write down 8 as next digit of the result. 
Result so far: 126282.8
Subtracting 5168 from 5560 leaves us with 392.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3920, and continue the process.

Let's proceed to step 10:
The number 646 fits into 3920 6 times, leaving a remainder of 44.
Put 6 as the next digit of the answer. 
Result so far: 126282.86
Subtract 3876 from 3920 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.

Advancing to step 11:
646 goes into 440 0 times with a remainder of 440.
Use 0 as the next digit of our solution. 
Result so far: 126282.86
The remainder is 440 after subtracting 0 from 440.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4400, and continue the process.

Moving on to step 12:
When dividing 4400 by 646, we get 6 with a remainder of 524.
Write down 6 as next digit of the result. 
Result so far: 126282.8606
Subtracting 3876 from 4400 leaves us with 524.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5240, and continue the process.

Advancing to step 13:
646 goes into 5240 8 times with a remainder of 72.
Write down 8 as next digit of the result. 
Result so far: 126282.86068
The remainder is 72 after subtracting 5168 from 5240.
Since there are no more digits in the dividend, we add a zero to the remainder making it 720, and continue the process.

On to step 14:
If we divide 720 by 646, we get 1 and a remainder of 74.
Use 1 as the next digit of our solution. 
Result so far: 126282.860681
Subtracting 646 from 720 leaves us with 74.
Since there are no more digits in the dividend, we add a zero to the remainder making it 740, and continue the process.

Let's proceed to step 15:
646 can be fit into 740 1 times, resulting in a remainder of 94.
Write down 1 as next digit of the result. 
Result so far: 126282.8606811
Subtracting 646 from 740 leaves us with 94.
Since there are no more digits in the dividend, we add a zero to the remainder making it 940, and continue the process.

After the division, we end up with 126282.8606811 and a remainder of 9.4e-07.