We divide 641388 by 16
We want to figure out the number of times 641388 can be divided by 16.

On to step 1:
The number 16 fits into 6 0 times, leaving a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Bring next digit (4) of the dividend behind the 6 and repeat the process: 64 / 16

Advancing to step 2:
The number 16 fits into 64 4 times, leaving a remainder of 0.
Write down 4 as next digit of the result. 
Result so far: 4.0
The remainder is 0 after subtracting 64 from 64.
Include the next digit (1) from the dividend after 0, then repeat: 1 / 16

On to step 3:
When dividing 1 by 16, we get 0 with a remainder of 1.
The next digit of our result is 0. 
Result so far: 40.0
The remainder is 1 after subtracting 0 from 1.
Bring next digit (3) of the dividend behind the 1 and repeat the process: 13 / 16

Advancing to step 4:
If we divide 13 by 16, we get 0 and a remainder of 13.
The next digit of our result is 0. 
Result so far: 400.0
Deduct 0 from 13 and we're left with 13.
Bring next digit (8) of the dividend behind the 13 and repeat the process: 138 / 16

On to step 5:
The number 16 fits into 138 8 times, leaving a remainder of 10.
Put 8 as the next digit of the answer. 
Result so far: 4008.0
If we take 128 away from 138, we end up with 10.
Take the next digit (8) from the dividend and append it to 10, then repeat: 108 / 16

On to step 6:
The number 16 fits into 108 6 times, leaving a remainder of 12.
The number 6 becomes the next digit in our result. 
Result so far: 40086.0
The remainder is 12 after subtracting 96 from 108.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Moving on to step 7:
16 can be fit into 120 7 times, resulting in a remainder of 8.
Write down 7 as next digit of the result. 
Result so far: 40086.7
If we subtract 112 from 120, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 8:
80 divided by 16 is 5 with a remainder of 0.
The next digit of our result is 5. 
Result so far: 40086.75
If we take 80 away from 80, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Step 9:
The number 16 fits into 0 0 times, leaving a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 40086.75
If we take 0 away from 0, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 10:
If we divide 0 by 16, we get 0 and a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 40086.75
If we take 0 away from 0, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final result is 40086.75 with a remainder of 0.0.