We look at the division of 45378648 by 644 
Our goal is to divide 45378648 by 644.

Let's proceed to step 1:
When dividing 4 by 644, we get 0 with a remainder of 4.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Bring next digit (5) of the dividend behind the 4 and repeat the process: 45 / 644

Advancing to step 2:
644 goes into 45 0 times with a remainder of 45.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 45, we end up with 45.
Bring next digit (3) of the dividend behind the 45 and repeat the process: 453 / 644

Moving on to step 3:
When dividing 453 by 644, we get 0 with a remainder of 453.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 453 to get 453.
Include the next digit (7) from the dividend after 453, then repeat: 4537 / 644

On to step 4:
644 goes into 4537 7 times with a remainder of 29.
The next digit of our result is 7. 
Result so far: 7.0
If we subtract 4508 from 4537, we get 29.
Append the next digit (8) from the dividend to 29 and continue with: 298 / 644

On to step 5:
If we divide 298 by 644, we get 0 and a remainder of 298.
Put 0 as the next digit of the answer. 
Result so far: 70.0
The remainder is 298 after subtracting 0 from 298.
Take the next digit (6) from the dividend and append it to 298, then repeat: 2986 / 644

Moving on to step 6:
644 can be fit into 2986 4 times, resulting in a remainder of 410.
Write down 4 as next digit of the result. 
Result so far: 704.0
The remainder is 410 after subtracting 2576 from 2986.
Grab the next digit (4) from the dividend, add it to 410, then carry on: 4104 / 644

Step 7:
The number 644 fits into 4104 6 times, leaving a remainder of 240.
Use 6 as the next digit of our solution. 
Result so far: 7046.0
If we take 3864 away from 4104, we end up with 240.
Include the next digit (8) from the dividend after 240, then repeat: 2408 / 644

On to step 8:
644 can be fit into 2408 3 times, resulting in a remainder of 476.
Use 3 as the next digit of our solution. 
Result so far: 70463.0
The remainder is 476 after subtracting 1932 from 2408.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4760, and continue the process.

Advancing to step 9:
644 can be fit into 4760 7 times, resulting in a remainder of 252.
The number 7 becomes the next digit in our result. 
Result so far: 70463.7
If we subtract 4508 from 4760, we get 252.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2520, and continue the process.

Step 10:
644 can be fit into 2520 3 times, resulting in a remainder of 588.
The next digit of our result is 3. 
Result so far: 70463.73
If we subtract 1932 from 2520, we get 588.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5880, and continue the process.

Step 11:
644 goes into 5880 9 times with a remainder of 84.
The number 9 becomes the next digit in our result. 
Result so far: 70463.739
Subtract 5796 from 5880 to get 84.
Since there are no more digits in the dividend, we add a zero to the remainder making it 840, and continue the process.

Going ahead to step 12:
The number 644 fits into 840 1 times, leaving a remainder of 196.
Record the quotient 1 as the next digit in the result. 
Result so far: 70463.7391
Subtract 644 from 840 to get 196.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1960, and continue the process.

On to step 13:
If we divide 1960 by 644, we get 3 and a remainder of 28.
Use 3 as the next digit of our solution. 
Result so far: 70463.73913
Subtract 1932 from 1960 to get 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

Let's proceed to step 14:
644 goes into 280 0 times with a remainder of 280.
Write down 0 as next digit of the result. 
Result so far: 70463.73913
Subtracting 0 from 280 leaves us with 280.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2800, and continue the process.

Advancing to step 15:
644 can be fit into 2800 4 times, resulting in a remainder of 224.
The number 4 becomes the next digit in our result. 
Result so far: 70463.7391304
Deduct 2576 from 2800 and we're left with 224.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2240, and continue the process.

Going ahead to step 16:
2240 divided by 644 is 3 with a remainder of 308.
Use 3 as the next digit of our solution. 
Result so far: 70463.73913043
If we subtract 1932 from 2240, we get 308.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3080, and continue the process.

After the division, we end up with 70463.73913043 and a remainder of 3.08e-07.