Let's divide 15993680 by 644
Our goal is to divide 15993680 by 644.

On to step 1:
644 can be fit into 1 0 times, resulting in a remainder of 1.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Take the next digit (5) from the dividend and append it to 1, then repeat: 15 / 644

Moving on to step 2:
The number 644 fits into 15 0 times, leaving a remainder of 15.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 15 and we're left with 15.
Grab the next digit (9) from the dividend, add it to 15, then carry on: 159 / 644

Let's proceed to step 3:
If we divide 159 by 644, we get 0 and a remainder of 159.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 159 to get 159.
Take the next digit (9) from the dividend and append it to 159, then repeat: 1599 / 644

Step 4:
If we divide 1599 by 644, we get 2 and a remainder of 311.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
If we subtract 1288 from 1599, we get 311.
Append the next digit (3) from the dividend to 311 and continue with: 3113 / 644

Moving on to step 5:
When dividing 3113 by 644, we get 4 with a remainder of 537.
Write down 4 as next digit of the result. 
Result so far: 24.0
If we subtract 2576 from 3113, we get 537.
Fetch the next digit (6) from the dividend, attach it to 537 and continue: 5376 / 644

Let's proceed to step 6:
If we divide 5376 by 644, we get 8 and a remainder of 224.
The next digit of our result is 8. 
Result so far: 248.0
If we take 5152 away from 5376, we end up with 224.
Take the next digit (8) from the dividend and append it to 224, then repeat: 2248 / 644

Let's proceed to step 7:
If we divide 2248 by 644, we get 3 and a remainder of 316.
Record the quotient 3 as the next digit in the result. 
Result so far: 2483.0
Subtracting 1932 from 2248 leaves us with 316.
Include the next digit (0) from the dividend after 316, then repeat: 3160 / 644

Step 8:
644 goes into 3160 4 times with a remainder of 584.
Record the quotient 4 as the next digit in the result. 
Result so far: 24834.0
Deduct 2576 from 3160 and we're left with 584.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5840, and continue the process.

Step 9:
If we divide 5840 by 644, we get 9 and a remainder of 44.
The next digit of our result is 9. 
Result so far: 24834.9
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.

Going ahead to step 10:
When dividing 440 by 644, we get 0 with a remainder of 440.
Record the quotient 0 as the next digit in the result. 
Result so far: 24834.9
If we subtract 0 from 440, we get 440.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4400, and continue the process.

Moving on to step 11:
4400 divided by 644 is 6 with a remainder of 536.
Use 6 as the next digit of our solution. 
Result so far: 24834.906
If we subtract 3864 from 4400, we get 536.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5360, and continue the process.

On to step 12:
When dividing 5360 by 644, we get 8 with a remainder of 208.
Put 8 as the next digit of the answer. 
Result so far: 24834.9068
The remainder is 208 after subtracting 5152 from 5360.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2080, and continue the process.

Let's proceed to step 13:
The number 644 fits into 2080 3 times, leaving a remainder of 148.
Write down 3 as next digit of the result. 
Result so far: 24834.90683
Subtract 1932 from 2080 to get 148.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1480, and continue the process.

Step 14:
644 goes into 1480 2 times with a remainder of 192.
Put 2 as the next digit of the answer. 
Result so far: 24834.906832
Subtracting 1288 from 1480 leaves us with 192.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1920, and continue the process.

Advancing to step 15:
The number 644 fits into 1920 2 times, leaving a remainder of 632.
Record the quotient 2 as the next digit in the result. 
Result so far: 24834.9068322
Deduct 1288 from 1920 and we're left with 632.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6320, and continue the process.

In conclusion, the division gives 24834.9068322 with a balance of 6.32e-06.