We look at the division of 40920439 by 644 
The aim is to understand the frequency of 644 in 40920439.

Going ahead to step 1:
If we divide 4 by 644, we get 0 and a remainder of 4.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 4, we get 4.
Append the next digit (0) from the dividend to 4 and continue with: 40 / 644

Going ahead to step 2:
When dividing 40 by 644, we get 0 with a remainder of 40.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 40, we end up with 40.
Append the next digit (9) from the dividend to 40 and continue with: 409 / 644

Moving on to step 3:
When dividing 409 by 644, we get 0 with a remainder of 409.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 409 after subtracting 0 from 409.
Grab the next digit (2) from the dividend, add it to 409, then carry on: 4092 / 644

Going ahead to step 4:
The number 644 fits into 4092 6 times, leaving a remainder of 228.
Record the quotient 6 as the next digit in the result. 
Result so far: 6.0
The remainder is 228 after subtracting 3864 from 4092.
Bring next digit (0) of the dividend behind the 228 and repeat the process: 2280 / 644

Moving on to step 5:
If we divide 2280 by 644, we get 3 and a remainder of 348.
Record the quotient 3 as the next digit in the result. 
Result so far: 63.0
If we take 1932 away from 2280, we end up with 348.
Append the next digit (4) from the dividend to 348 and continue with: 3484 / 644

Let's proceed to step 6:
When dividing 3484 by 644, we get 5 with a remainder of 264.
The number 5 becomes the next digit in our result. 
Result so far: 635.0
Subtracting 3220 from 3484 leaves us with 264.
Append the next digit (3) from the dividend to 264 and continue with: 2643 / 644

Going ahead to step 7:
644 can be fit into 2643 4 times, resulting in a remainder of 67.
Write down 4 as next digit of the result. 
Result so far: 6354.0
The remainder is 67 after subtracting 2576 from 2643.
Take the next digit (9) from the dividend and append it to 67, then repeat: 679 / 644

Let's proceed to step 8:
If we divide 679 by 644, we get 1 and a remainder of 35.
Use 1 as the next digit of our solution. 
Result so far: 63541.0
Subtracting 644 from 679 leaves us with 35.
Since there are no more digits in the dividend, we add a zero to the remainder making it 350, and continue the process.

Step 9:
When dividing 350 by 644, we get 0 with a remainder of 350.
The number 0 becomes the next digit in our result. 
Result so far: 63541.0
If we take 0 away from 350, we end up with 350.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3500, and continue the process.

Let's proceed to step 10:
644 can be fit into 3500 5 times, resulting in a remainder of 280.
Write down 5 as next digit of the result. 
Result so far: 63541.05
The remainder is 280 after subtracting 3220 from 3500.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2800, and continue the process.

Advancing to step 11:
2800 divided by 644 is 4 with a remainder of 224.
The number 4 becomes the next digit in our result. 
Result so far: 63541.054
Subtracting 2576 from 2800 leaves us with 224.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2240, and continue the process.

On to step 12:
When dividing 2240 by 644, we get 3 with a remainder of 308.
Put 3 as the next digit of the answer. 
Result so far: 63541.0543
The remainder is 308 after subtracting 1932 from 2240.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3080, and continue the process.

Step 13:
3080 divided by 644 is 4 with a remainder of 504.
Write down 4 as next digit of the result. 
Result so far: 63541.05434
Subtracting 2576 from 3080 leaves us with 504.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5040, and continue the process.

On to step 14:
If we divide 5040 by 644, we get 7 and a remainder of 532.
The next digit of our result is 7. 
Result so far: 63541.054347
Subtract 4508 from 5040 to get 532.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5320, and continue the process.

Advancing to step 15:
644 can be fit into 5320 8 times, resulting in a remainder of 168.
Write down 8 as next digit of the result. 
Result so far: 63541.0543478
Subtracting 5152 from 5320 leaves us with 168.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1680, and continue the process.

Let's proceed to step 16:
644 can be fit into 1680 2 times, resulting in a remainder of 392.
Record the quotient 2 as the next digit in the result. 
Result so far: 63541.05434782
Subtract 1288 from 1680 to get 392.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3920, and continue the process.

In conclusion, the division gives 63541.05434782 with a balance of 3.92e-07.