We look at the division of 305268 by 72 
The aim is to understand the frequency of 72 in 305268.

On to step 1:
3 divided by 72 is 0 with a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 3, we get 3.
Append the next digit (0) from the dividend to 3 and continue with: 30 / 72

Going ahead to step 2:
The number 72 fits into 30 0 times, leaving a remainder of 30.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 30, we end up with 30.
Fetch the next digit (5) from the dividend, attach it to 30 and continue: 305 / 72

Going ahead to step 3:
When dividing 305 by 72, we get 4 with a remainder of 17.
The next digit of our result is 4. 
Result so far: 4.0
If we subtract 288 from 305, we get 17.
Append the next digit (2) from the dividend to 17 and continue with: 172 / 72

Advancing to step 4:
When dividing 172 by 72, we get 2 with a remainder of 28.
The next digit of our result is 2. 
Result so far: 42.0
If we subtract 144 from 172, we get 28.
Bring next digit (6) of the dividend behind the 28 and repeat the process: 286 / 72

On to step 5:
If we divide 286 by 72, we get 3 and a remainder of 70.
Put 3 as the next digit of the answer. 
Result so far: 423.0
If we take 216 away from 286, we end up with 70.
Append the next digit (8) from the dividend to 70 and continue with: 708 / 72

On to step 6:
72 goes into 708 9 times with a remainder of 60.
Write down 9 as next digit of the result. 
Result so far: 4239.0
Deduct 648 from 708 and we're left with 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Step 7:
72 can be fit into 600 8 times, resulting in a remainder of 24.
Put 8 as the next digit of the answer. 
Result so far: 4239.8
Subtracting 576 from 600 leaves us with 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Advancing to step 8:
72 goes into 240 3 times with a remainder of 24.
Put 3 as the next digit of the answer. 
Result so far: 4239.83
The remainder is 24 after subtracting 216 from 240.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Step 9:
When dividing 240 by 72, we get 3 with a remainder of 24.
Put 3 as the next digit of the answer. 
Result so far: 4239.833
Subtracting 216 from 240 leaves us with 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

The final result is 4239.833 with a remainder of 0.0024.