We're dividing 644430 by 72 
The aim is to understand the frequency of 72 in 644430.

Going ahead to step 1:
If we divide 6 by 72, we get 0 and a remainder of 6.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Grab the next digit (4) from the dividend, add it to 6, then carry on: 64 / 72

On to step 2:
72 can be fit into 64 0 times, resulting in a remainder of 64.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 64 to get 64.
Append the next digit (4) from the dividend to 64 and continue with: 644 / 72

Step 3:
72 goes into 644 8 times with a remainder of 68.
Use 8 as the next digit of our solution. 
Result so far: 8.0
Deduct 576 from 644 and we're left with 68.
Include the next digit (4) from the dividend after 68, then repeat: 684 / 72

Advancing to step 4:
If we divide 684 by 72, we get 9 and a remainder of 36.
Use 9 as the next digit of our solution. 
Result so far: 89.0
Deduct 648 from 684 and we're left with 36.
Grab the next digit (3) from the dividend, add it to 36, then carry on: 363 / 72

Let's proceed to step 5:
When dividing 363 by 72, we get 5 with a remainder of 3.
Write down 5 as next digit of the result. 
Result so far: 895.0
Subtracting 360 from 363 leaves us with 3.
Bring next digit (0) of the dividend behind the 3 and repeat the process: 30 / 72

Advancing to step 6:
72 goes into 30 0 times with a remainder of 30.
Put 0 as the next digit of the answer. 
Result so far: 8950.0
Subtracting 0 from 30 leaves us with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Moving on to step 7:
300 divided by 72 is 4 with a remainder of 12.
Write down 4 as next digit of the result. 
Result so far: 8950.4
If we subtract 288 from 300, we get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Going ahead to step 8:
If we divide 120 by 72, we get 1 and a remainder of 48.
The number 1 becomes the next digit in our result. 
Result so far: 8950.41
The remainder is 48 after subtracting 72 from 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

Step 9:
When dividing 480 by 72, we get 6 with a remainder of 48.
Record the quotient 6 as the next digit in the result. 
Result so far: 8950.416
Subtract 432 from 480 to get 48.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

Step 10:
72 goes into 480 6 times with a remainder of 48.
Put 6 as the next digit of the answer. 
Result so far: 8950.4166
Subtract 432 from 480 to get 48.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

The quotient of the division is 8950.4166, and the remainder is 0.00048.