We divide 644650 by 12
We want to divide 644650 by 12.

On to step 1:
The number 12 fits into 6 0 times, leaving a remainder of 6.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Take the next digit (4) from the dividend and append it to 6, then repeat: 64 / 12

Step 2:
The number 12 fits into 64 5 times, leaving a remainder of 4.
Write down 5 as next digit of the result. 
Result so far: 5.0
Deduct 60 from 64 and we're left with 4.
Fetch the next digit (4) from the dividend, attach it to 4 and continue: 44 / 12

Going ahead to step 3:
If we divide 44 by 12, we get 3 and a remainder of 8.
Use 3 as the next digit of our solution. 
Result so far: 53.0
The remainder is 8 after subtracting 36 from 44.
Append the next digit (6) from the dividend to 8 and continue with: 86 / 12

Advancing to step 4:
When dividing 86 by 12, we get 7 with a remainder of 2.
The number 7 becomes the next digit in our result. 
Result so far: 537.0
Subtract 84 from 86 to get 2.
Grab the next digit (5) from the dividend, add it to 2, then carry on: 25 / 12

Let's proceed to step 5:
12 can be fit into 25 2 times, resulting in a remainder of 1.
The number 2 becomes the next digit in our result. 
Result so far: 5372.0
If we take 24 away from 25, we end up with 1.
Append the next digit (0) from the dividend to 1 and continue with: 10 / 12

Going ahead to step 6:
If we divide 10 by 12, we get 0 and a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 53720.0
Subtracting 0 from 10 leaves us with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Step 7:
100 divided by 12 is 8 with a remainder of 4.
The number 8 becomes the next digit in our result. 
Result so far: 53720.8
The remainder is 4 after subtracting 96 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Let's proceed to step 8:
When dividing 40 by 12, we get 3 with a remainder of 4.
The next digit of our result is 3. 
Result so far: 53720.83
If we take 36 away from 40, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Moving on to step 9:
12 can be fit into 40 3 times, resulting in a remainder of 4.
Use 3 as the next digit of our solution. 
Result so far: 53720.833
If we take 36 away from 40, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

The final result is 53720.833 with a remainder of 0.0004.