90289712 ÷ 644 
We want to divide 90289712 by 644.

Step 1:
The number 644 fits into 9 0 times, leaving a remainder of 9.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 9 and we're left with 9.
Include the next digit (0) from the dividend after 9, then repeat: 90 / 644

On to step 2:
90 divided by 644 is 0 with a remainder of 90.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 90, we end up with 90.
Grab the next digit (2) from the dividend, add it to 90, then carry on: 902 / 644

Let's proceed to step 3:
644 can be fit into 902 1 times, resulting in a remainder of 258.
Put 1 as the next digit of the answer. 
Result so far: 1.0
If we take 644 away from 902, we end up with 258.
Grab the next digit (8) from the dividend, add it to 258, then carry on: 2588 / 644

Let's proceed to step 4:
644 can be fit into 2588 4 times, resulting in a remainder of 12.
Write down 4 as next digit of the result. 
Result so far: 14.0
If we take 2576 away from 2588, we end up with 12.
Append the next digit (9) from the dividend to 12 and continue with: 129 / 644

Going ahead to step 5:
644 goes into 129 0 times with a remainder of 129.
Put 0 as the next digit of the answer. 
Result so far: 140.0
If we subtract 0 from 129, we get 129.
Take the next digit (7) from the dividend and append it to 129, then repeat: 1297 / 644

Step 6:
If we divide 1297 by 644, we get 2 and a remainder of 9.
The number 2 becomes the next digit in our result. 
Result so far: 1402.0
If we take 1288 away from 1297, we end up with 9.
Include the next digit (1) from the dividend after 9, then repeat: 91 / 644

Advancing to step 7:
644 goes into 91 0 times with a remainder of 91.
Use 0 as the next digit of our solution. 
Result so far: 14020.0
If we subtract 0 from 91, we get 91.
Include the next digit (2) from the dividend after 91, then repeat: 912 / 644

Step 8:
If we divide 912 by 644, we get 1 and a remainder of 268.
The number 1 becomes the next digit in our result. 
Result so far: 140201.0
If we take 644 away from 912, we end up with 268.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2680, and continue the process.

Going ahead to step 9:
644 goes into 2680 4 times with a remainder of 104.
Record the quotient 4 as the next digit in the result. 
Result so far: 140201.4
The remainder is 104 after subtracting 2576 from 2680.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1040, and continue the process.

Step 10:
644 can be fit into 1040 1 times, resulting in a remainder of 396.
Put 1 as the next digit of the answer. 
Result so far: 140201.41
Subtract 644 from 1040 to get 396.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3960, and continue the process.

On to step 11:
3960 divided by 644 is 6 with a remainder of 96.
The number 6 becomes the next digit in our result. 
Result so far: 140201.416
If we subtract 3864 from 3960, we get 96.
Since there are no more digits in the dividend, we add a zero to the remainder making it 960, and continue the process.

Step 12:
644 goes into 960 1 times with a remainder of 316.
Record the quotient 1 as the next digit in the result. 
Result so far: 140201.4161
Subtracting 644 from 960 leaves us with 316.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3160, and continue the process.

Step 13:
The number 644 fits into 3160 4 times, leaving a remainder of 584.
The next digit of our result is 4. 
Result so far: 140201.41614
The remainder is 584 after subtracting 2576 from 3160.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5840, and continue the process.

Going ahead to step 14:
The number 644 fits into 5840 9 times, leaving a remainder of 44.
Put 9 as the next digit of the answer. 
Result so far: 140201.416149
The remainder is 44 after subtracting 5796 from 5840.
Since there are no more digits in the dividend, we add a zero to the remainder making it 440, and continue the process.

On to step 15:
The number 644 fits into 440 0 times, leaving a remainder of 440.
Use 0 as the next digit of our solution. 
Result so far: 140201.416149
Deduct 0 from 440 and we're left with 440.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4400, and continue the process.

Advancing to step 16:
644 can be fit into 4400 6 times, resulting in a remainder of 536.
Put 6 as the next digit of the answer. 
Result so far: 140201.41614906
The remainder is 536 after subtracting 3864 from 4400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5360, and continue the process.

After the division, we end up with 140201.41614906 and a remainder of 5.36e-07.