98876321 ÷ 644 
We want to divide 98876321 by 644.

Moving on to step 1:
9 divided by 644 is 0 with a remainder of 9.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 9 and we're left with 9.
Fetch the next digit (8) from the dividend, attach it to 9 and continue: 98 / 644

On to step 2:
The number 644 fits into 98 0 times, leaving a remainder of 98.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 98 leaves us with 98.
Grab the next digit (8) from the dividend, add it to 98, then carry on: 988 / 644

Step 3:
644 goes into 988 1 times with a remainder of 344.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we subtract 644 from 988, we get 344.
Take the next digit (7) from the dividend and append it to 344, then repeat: 3447 / 644

Step 4:
When dividing 3447 by 644, we get 5 with a remainder of 227.
The next digit of our result is 5. 
Result so far: 15.0
The remainder is 227 after subtracting 3220 from 3447.
Take the next digit (6) from the dividend and append it to 227, then repeat: 2276 / 644

Advancing to step 5:
When dividing 2276 by 644, we get 3 with a remainder of 344.
Put 3 as the next digit of the answer. 
Result so far: 153.0
The remainder is 344 after subtracting 1932 from 2276.
Grab the next digit (3) from the dividend, add it to 344, then carry on: 3443 / 644

Let's proceed to step 6:
The number 644 fits into 3443 5 times, leaving a remainder of 223.
The number 5 becomes the next digit in our result. 
Result so far: 1535.0
The remainder is 223 after subtracting 3220 from 3443.
Include the next digit (2) from the dividend after 223, then repeat: 2232 / 644

Advancing to step 7:
644 can be fit into 2232 3 times, resulting in a remainder of 300.
Record the quotient 3 as the next digit in the result. 
Result so far: 15353.0
Deduct 1932 from 2232 and we're left with 300.
Grab the next digit (1) from the dividend, add it to 300, then carry on: 3001 / 644

Moving on to step 8:
644 goes into 3001 4 times with a remainder of 425.
Record the quotient 4 as the next digit in the result. 
Result so far: 153534.0
If we subtract 2576 from 3001, we get 425.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4250, and continue the process.

Step 9:
4250 divided by 644 is 6 with a remainder of 386.
The number 6 becomes the next digit in our result. 
Result so far: 153534.6
Subtract 3864 from 4250 to get 386.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3860, and continue the process.

Moving on to step 10:
If we divide 3860 by 644, we get 5 and a remainder of 640.
Put 5 as the next digit of the answer. 
Result so far: 153534.65
Deduct 3220 from 3860 and we're left with 640.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6400, and continue the process.

Step 11:
If we divide 6400 by 644, we get 9 and a remainder of 604.
Write down 9 as next digit of the result. 
Result so far: 153534.659
Subtract 5796 from 6400 to get 604.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6040, and continue the process.

Step 12:
6040 divided by 644 is 9 with a remainder of 244.
The number 9 becomes the next digit in our result. 
Result so far: 153534.6599
The remainder is 244 after subtracting 5796 from 6040.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2440, and continue the process.

The final outcome is 153534.6599, with a leftover of 0.00244.