52387607 ÷ 644 
The aim is to understand the frequency of 644 in 52387607.

Step 1:
If we divide 5 by 644, we get 0 and a remainder of 5.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 5, we get 5.
Include the next digit (2) from the dividend after 5, then repeat: 52 / 644

On to step 2:
644 goes into 52 0 times with a remainder of 52.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 52, we get 52.
Fetch the next digit (3) from the dividend, attach it to 52 and continue: 523 / 644

On to step 3:
The number 644 fits into 523 0 times, leaving a remainder of 523.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 523 after subtracting 0 from 523.
Include the next digit (8) from the dividend after 523, then repeat: 5238 / 644

Let's proceed to step 4:
When dividing 5238 by 644, we get 8 with a remainder of 86.
The next digit of our result is 8. 
Result so far: 8.0
Subtracting 5152 from 5238 leaves us with 86.
Append the next digit (7) from the dividend to 86 and continue with: 867 / 644

Let's proceed to step 5:
644 can be fit into 867 1 times, resulting in a remainder of 223.
Put 1 as the next digit of the answer. 
Result so far: 81.0
Subtract 644 from 867 to get 223.
Append the next digit (6) from the dividend to 223 and continue with: 2236 / 644

Step 6:
If we divide 2236 by 644, we get 3 and a remainder of 304.
The number 3 becomes the next digit in our result. 
Result so far: 813.0
If we take 1932 away from 2236, we end up with 304.
Fetch the next digit (0) from the dividend, attach it to 304 and continue: 3040 / 644

Moving on to step 7:
3040 divided by 644 is 4 with a remainder of 464.
The number 4 becomes the next digit in our result. 
Result so far: 8134.0
The remainder is 464 after subtracting 2576 from 3040.
Append the next digit (7) from the dividend to 464 and continue with: 4647 / 644

Advancing to step 8:
When dividing 4647 by 644, we get 7 with a remainder of 139.
Record the quotient 7 as the next digit in the result. 
Result so far: 81347.0
Deduct 4508 from 4647 and we're left with 139.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1390, and continue the process.

Step 9:
644 can be fit into 1390 2 times, resulting in a remainder of 102.
Record the quotient 2 as the next digit in the result. 
Result so far: 81347.2
Subtract 1288 from 1390 to get 102.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1020, and continue the process.

Let's proceed to step 10:
The number 644 fits into 1020 1 times, leaving a remainder of 376.
Use 1 as the next digit of our solution. 
Result so far: 81347.21
Deduct 644 from 1020 and we're left with 376.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3760, and continue the process.

Advancing to step 11:
When dividing 3760 by 644, we get 5 with a remainder of 540.
The next digit of our result is 5. 
Result so far: 81347.215
Subtracting 3220 from 3760 leaves us with 540.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5400, and continue the process.

On to step 12:
If we divide 5400 by 644, we get 8 and a remainder of 248.
Put 8 as the next digit of the answer. 
Result so far: 81347.2158
If we subtract 5152 from 5400, we get 248.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2480, and continue the process.

Moving on to step 13:
644 can be fit into 2480 3 times, resulting in a remainder of 548.
Use 3 as the next digit of our solution. 
Result so far: 81347.21583
The remainder is 548 after subtracting 1932 from 2480.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5480, and continue the process.

Going ahead to step 14:
5480 divided by 644 is 8 with a remainder of 328.
The number 8 becomes the next digit in our result. 
Result so far: 81347.215838
Subtract 5152 from 5480 to get 328.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3280, and continue the process.

On to step 15:
The number 644 fits into 3280 5 times, leaving a remainder of 60.
The number 5 becomes the next digit in our result. 
Result so far: 81347.2158385
Subtract 3220 from 3280 to get 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Going ahead to step 16:
644 can be fit into 600 0 times, resulting in a remainder of 600.
Put 0 as the next digit of the answer. 
Result so far: 81347.2158385
If we take 0 away from 600, we end up with 600.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6000, and continue the process.

The quotient of the division is 81347.2158385, and the remainder is 6e-07.