91930578 divided by 644 
We want to figure out the number of times 91930578 can be divided by 644.

On to step 1:
If we divide 9 by 644, we get 0 and a remainder of 9.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 9 to get 9.
Fetch the next digit (1) from the dividend, attach it to 9 and continue: 91 / 644

Moving on to step 2:
644 goes into 91 0 times with a remainder of 91.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 91, we get 91.
Include the next digit (9) from the dividend after 91, then repeat: 919 / 644

Advancing to step 3:
When dividing 919 by 644, we get 1 with a remainder of 275.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Deduct 644 from 919 and we're left with 275.
Bring next digit (3) of the dividend behind the 275 and repeat the process: 2753 / 644

On to step 4:
644 goes into 2753 4 times with a remainder of 177.
The next digit of our result is 4. 
Result so far: 14.0
Subtract 2576 from 2753 to get 177.
Bring next digit (0) of the dividend behind the 177 and repeat the process: 1770 / 644

Step 5:
When dividing 1770 by 644, we get 2 with a remainder of 482.
Record the quotient 2 as the next digit in the result. 
Result so far: 142.0
Deduct 1288 from 1770 and we're left with 482.
Append the next digit (5) from the dividend to 482 and continue with: 4825 / 644

Going ahead to step 6:
4825 divided by 644 is 7 with a remainder of 317.
Put 7 as the next digit of the answer. 
Result so far: 1427.0
If we subtract 4508 from 4825, we get 317.
Grab the next digit (7) from the dividend, add it to 317, then carry on: 3177 / 644

Advancing to step 7:
The number 644 fits into 3177 4 times, leaving a remainder of 601.
The next digit of our result is 4. 
Result so far: 14274.0
If we take 2576 away from 3177, we end up with 601.
Take the next digit (8) from the dividend and append it to 601, then repeat: 6018 / 644

Advancing to step 8:
6018 divided by 644 is 9 with a remainder of 222.
The next digit of our result is 9. 
Result so far: 142749.0
Subtracting 5796 from 6018 leaves us with 222.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2220, and continue the process.

Let's proceed to step 9:
The number 644 fits into 2220 3 times, leaving a remainder of 288.
Record the quotient 3 as the next digit in the result. 
Result so far: 142749.3
If we take 1932 away from 2220, we end up with 288.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2880, and continue the process.

Advancing to step 10:
644 can be fit into 2880 4 times, resulting in a remainder of 304.
The number 4 becomes the next digit in our result. 
Result so far: 142749.34
The remainder is 304 after subtracting 2576 from 2880.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3040, and continue the process.

On to step 11:
644 goes into 3040 4 times with a remainder of 464.
Use 4 as the next digit of our solution. 
Result so far: 142749.344
Subtract 2576 from 3040 to get 464.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4640, and continue the process.

Our division results in 142749.344 with a remaining 0.0464.