80778873 ÷ 644 
We want to figure out the number of times 80778873 can be divided by 644.

Going ahead to step 1:
The number 644 fits into 8 0 times, leaving a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 8 after subtracting 0 from 8.
Bring next digit (0) of the dividend behind the 8 and repeat the process: 80 / 644

Moving on to step 2:
The number 644 fits into 80 0 times, leaving a remainder of 80.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 80 to get 80.
Bring next digit (7) of the dividend behind the 80 and repeat the process: 807 / 644

Advancing to step 3:
644 can be fit into 807 1 times, resulting in a remainder of 163.
Write down 1 as next digit of the result. 
Result so far: 1.0
Deduct 644 from 807 and we're left with 163.
Grab the next digit (7) from the dividend, add it to 163, then carry on: 1637 / 644

Let's proceed to step 4:
1637 divided by 644 is 2 with a remainder of 349.
The next digit of our result is 2. 
Result so far: 12.0
If we subtract 1288 from 1637, we get 349.
Include the next digit (8) from the dividend after 349, then repeat: 3498 / 644

Let's proceed to step 5:
The number 644 fits into 3498 5 times, leaving a remainder of 278.
Write down 5 as next digit of the result. 
Result so far: 125.0
The remainder is 278 after subtracting 3220 from 3498.
Grab the next digit (8) from the dividend, add it to 278, then carry on: 2788 / 644

Moving on to step 6:
2788 divided by 644 is 4 with a remainder of 212.
The number 4 becomes the next digit in our result. 
Result so far: 1254.0
Deduct 2576 from 2788 and we're left with 212.
Take the next digit (7) from the dividend and append it to 212, then repeat: 2127 / 644

On to step 7:
644 can be fit into 2127 3 times, resulting in a remainder of 195.
Record the quotient 3 as the next digit in the result. 
Result so far: 12543.0
If we take 1932 away from 2127, we end up with 195.
Append the next digit (3) from the dividend to 195 and continue with: 1953 / 644

Moving on to step 8:
644 goes into 1953 3 times with a remainder of 21.
Write down 3 as next digit of the result. 
Result so far: 125433.0
Subtracting 1932 from 1953 leaves us with 21.
Since there are no more digits in the dividend, we add a zero to the remainder making it 210, and continue the process.

Advancing to step 9:
The number 644 fits into 210 0 times, leaving a remainder of 210.
Use 0 as the next digit of our solution. 
Result so far: 125433.0
If we take 0 away from 210, we end up with 210.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2100, and continue the process.

Let's proceed to step 10:
644 goes into 2100 3 times with a remainder of 168.
Write down 3 as next digit of the result. 
Result so far: 125433.03
Subtracting 1932 from 2100 leaves us with 168.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1680, and continue the process.

Going ahead to step 11:
644 goes into 1680 2 times with a remainder of 392.
Write down 2 as next digit of the result. 
Result so far: 125433.032
If we subtract 1288 from 1680, we get 392.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3920, and continue the process.

On to step 12:
644 goes into 3920 6 times with a remainder of 56.
The number 6 becomes the next digit in our result. 
Result so far: 125433.0326
If we subtract 3864 from 3920, we get 56.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

On to step 13:
The number 644 fits into 560 0 times, leaving a remainder of 560.
Write down 0 as next digit of the result. 
Result so far: 125433.0326
Deduct 0 from 560 and we're left with 560.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5600, and continue the process.

Let's proceed to step 14:
644 can be fit into 5600 8 times, resulting in a remainder of 448.
Record the quotient 8 as the next digit in the result. 
Result so far: 125433.032608
Subtract 5152 from 5600 to get 448.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4480, and continue the process.

Advancing to step 15:
When dividing 4480 by 644, we get 6 with a remainder of 616.
The number 6 becomes the next digit in our result. 
Result so far: 125433.0326086
If we subtract 3864 from 4480, we get 616.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6160, and continue the process.

Let's proceed to step 16:
644 goes into 6160 9 times with a remainder of 364.
Record the quotient 9 as the next digit in the result. 
Result so far: 125433.03260869
The remainder is 364 after subtracting 5796 from 6160.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3640, and continue the process.

The final outcome is 125433.03260869, with a leftover of 3.64e-07.