We look at the division of 39636712 by 644 
The aim is to understand the frequency of 644 in 39636712.

Let's proceed to step 1:
3 divided by 644 is 0 with a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 3 after subtracting 0 from 3.
Fetch the next digit (9) from the dividend, attach it to 3 and continue: 39 / 644

On to step 2:
The number 644 fits into 39 0 times, leaving a remainder of 39.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 39 leaves us with 39.
Include the next digit (6) from the dividend after 39, then repeat: 396 / 644

Step 3:
396 divided by 644 is 0 with a remainder of 396.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 396 to get 396.
Include the next digit (3) from the dividend after 396, then repeat: 3963 / 644

Advancing to step 4:
644 goes into 3963 6 times with a remainder of 99.
The next digit of our result is 6. 
Result so far: 6.0
The remainder is 99 after subtracting 3864 from 3963.
Include the next digit (6) from the dividend after 99, then repeat: 996 / 644

Step 5:
When dividing 996 by 644, we get 1 with a remainder of 352.
The number 1 becomes the next digit in our result. 
Result so far: 61.0
The remainder is 352 after subtracting 644 from 996.
Bring next digit (7) of the dividend behind the 352 and repeat the process: 3527 / 644

On to step 6:
The number 644 fits into 3527 5 times, leaving a remainder of 307.
Put 5 as the next digit of the answer. 
Result so far: 615.0
Subtracting 3220 from 3527 leaves us with 307.
Bring next digit (1) of the dividend behind the 307 and repeat the process: 3071 / 644

Let's proceed to step 7:
3071 divided by 644 is 4 with a remainder of 495.
Write down 4 as next digit of the result. 
Result so far: 6154.0
The remainder is 495 after subtracting 2576 from 3071.
Fetch the next digit (2) from the dividend, attach it to 495 and continue: 4952 / 644

Moving on to step 8:
644 goes into 4952 7 times with a remainder of 444.
The next digit of our result is 7. 
Result so far: 61547.0
Deduct 4508 from 4952 and we're left with 444.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4440, and continue the process.

Moving on to step 9:
The number 644 fits into 4440 6 times, leaving a remainder of 576.
Put 6 as the next digit of the answer. 
Result so far: 61547.6
If we take 3864 away from 4440, we end up with 576.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5760, and continue the process.

Moving on to step 10:
If we divide 5760 by 644, we get 8 and a remainder of 608.
Put 8 as the next digit of the answer. 
Result so far: 61547.68
The remainder is 608 after subtracting 5152 from 5760.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6080, and continue the process.

Step 11:
The number 644 fits into 6080 9 times, leaving a remainder of 284.
Use 9 as the next digit of our solution. 
Result so far: 61547.689
The remainder is 284 after subtracting 5796 from 6080.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2840, and continue the process.

Let's proceed to step 12:
644 goes into 2840 4 times with a remainder of 264.
Record the quotient 4 as the next digit in the result. 
Result so far: 61547.6894
The remainder is 264 after subtracting 2576 from 2840.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2640, and continue the process.

Advancing to step 13:
When dividing 2640 by 644, we get 4 with a remainder of 64.
The number 4 becomes the next digit in our result. 
Result so far: 61547.68944
If we take 2576 away from 2640, we end up with 64.
Since there are no more digits in the dividend, we add a zero to the remainder making it 640, and continue the process.

The final result is 61547.68944 with a remainder of 6.4e-05.