We look at the division of 29646939 by 648 
The aim is to understand the frequency of 648 in 29646939.

On to step 1:
648 can be fit into 2 0 times, resulting in a remainder of 2.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 2 to get 2.
Grab the next digit (9) from the dividend, add it to 2, then carry on: 29 / 648

Let's proceed to step 2:
The number 648 fits into 29 0 times, leaving a remainder of 29.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 29 after subtracting 0 from 29.
Grab the next digit (6) from the dividend, add it to 29, then carry on: 296 / 648

Let's proceed to step 3:
If we divide 296 by 648, we get 0 and a remainder of 296.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 296 leaves us with 296.
Append the next digit (4) from the dividend to 296 and continue with: 2964 / 648

Step 4:
648 can be fit into 2964 4 times, resulting in a remainder of 372.
Use 4 as the next digit of our solution. 
Result so far: 4.0
The remainder is 372 after subtracting 2592 from 2964.
Include the next digit (6) from the dividend after 372, then repeat: 3726 / 648

Moving on to step 5:
3726 divided by 648 is 5 with a remainder of 486.
Record the quotient 5 as the next digit in the result. 
Result so far: 45.0
Subtracting 3240 from 3726 leaves us with 486.
Grab the next digit (9) from the dividend, add it to 486, then carry on: 4869 / 648

On to step 6:
The number 648 fits into 4869 7 times, leaving a remainder of 333.
The next digit of our result is 7. 
Result so far: 457.0
Deduct 4536 from 4869 and we're left with 333.
Grab the next digit (3) from the dividend, add it to 333, then carry on: 3333 / 648

Going ahead to step 7:
3333 divided by 648 is 5 with a remainder of 93.
The next digit of our result is 5. 
Result so far: 4575.0
The remainder is 93 after subtracting 3240 from 3333.
Append the next digit (9) from the dividend to 93 and continue with: 939 / 648

Let's proceed to step 8:
The number 648 fits into 939 1 times, leaving a remainder of 291.
Write down 1 as next digit of the result. 
Result so far: 45751.0
If we take 648 away from 939, we end up with 291.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2910, and continue the process.

On to step 9:
648 can be fit into 2910 4 times, resulting in a remainder of 318.
Write down 4 as next digit of the result. 
Result so far: 45751.4
If we subtract 2592 from 2910, we get 318.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3180, and continue the process.

Moving on to step 10:
648 goes into 3180 4 times with a remainder of 588.
Put 4 as the next digit of the answer. 
Result so far: 45751.44
If we subtract 2592 from 3180, we get 588.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5880, and continue the process.

The final outcome is 45751.44, with a leftover of 0.588.