We're dividing 64921511 by 648 
The aim is to understand the frequency of 648 in 64921511.

Step 1:
648 can be fit into 6 0 times, resulting in a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Include the next digit (4) from the dividend after 6, then repeat: 64 / 648

Step 2:
The number 648 fits into 64 0 times, leaving a remainder of 64.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 64 leaves us with 64.
Fetch the next digit (9) from the dividend, attach it to 64 and continue: 649 / 648

Let's proceed to step 3:
648 goes into 649 1 times with a remainder of 1.
Put 1 as the next digit of the answer. 
Result so far: 1.0
The remainder is 1 after subtracting 648 from 649.
Take the next digit (2) from the dividend and append it to 1, then repeat: 12 / 648

On to step 4:
The number 648 fits into 12 0 times, leaving a remainder of 12.
The number 0 becomes the next digit in our result. 
Result so far: 10.0
The remainder is 12 after subtracting 0 from 12.
Append the next digit (1) from the dividend to 12 and continue with: 121 / 648

Advancing to step 5:
648 goes into 121 0 times with a remainder of 121.
The next digit of our result is 0. 
Result so far: 100.0
Subtract 0 from 121 to get 121.
Include the next digit (5) from the dividend after 121, then repeat: 1215 / 648

Advancing to step 6:
648 goes into 1215 1 times with a remainder of 567.
Write down 1 as next digit of the result. 
Result so far: 1001.0
If we subtract 648 from 1215, we get 567.
Bring next digit (1) of the dividend behind the 567 and repeat the process: 5671 / 648

Advancing to step 7:
648 can be fit into 5671 8 times, resulting in a remainder of 487.
Write down 8 as next digit of the result. 
Result so far: 10018.0
Subtract 5184 from 5671 to get 487.
Take the next digit (1) from the dividend and append it to 487, then repeat: 4871 / 648

Step 8:
648 can be fit into 4871 7 times, resulting in a remainder of 335.
The number 7 becomes the next digit in our result. 
Result so far: 100187.0
Deduct 4536 from 4871 and we're left with 335.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3350, and continue the process.

Let's proceed to step 9:
3350 divided by 648 is 5 with a remainder of 110.
Write down 5 as next digit of the result. 
Result so far: 100187.5
Deduct 3240 from 3350 and we're left with 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1100, and continue the process.

On to step 10:
If we divide 1100 by 648, we get 1 and a remainder of 452.
Put 1 as the next digit of the answer. 
Result so far: 100187.51
The remainder is 452 after subtracting 648 from 1100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4520, and continue the process.

Step 11:
648 goes into 4520 6 times with a remainder of 632.
Record the quotient 6 as the next digit in the result. 
Result so far: 100187.516
Subtracting 3888 from 4520 leaves us with 632.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6320, and continue the process.

Moving on to step 12:
When dividing 6320 by 648, we get 9 with a remainder of 488.
Write down 9 as next digit of the result. 
Result so far: 100187.5169
Deduct 5832 from 6320 and we're left with 488.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4880, and continue the process.

On to step 13:
4880 divided by 648 is 7 with a remainder of 344.
Write down 7 as next digit of the result. 
Result so far: 100187.51697
Subtracting 4536 from 4880 leaves us with 344.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3440, and continue the process.

Step 14:
When dividing 3440 by 648, we get 5 with a remainder of 200.
Put 5 as the next digit of the answer. 
Result so far: 100187.516975
Subtract 3240 from 3440 to get 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2000, and continue the process.

Advancing to step 15:
If we divide 2000 by 648, we get 3 and a remainder of 56.
The number 3 becomes the next digit in our result. 
Result so far: 100187.5169753
If we take 1944 away from 2000, we end up with 56.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

On to step 16:
648 goes into 560 0 times with a remainder of 560.
Record the quotient 0 as the next digit in the result. 
Result so far: 100187.5169753
Deduct 0 from 560 and we're left with 560.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5600, and continue the process.

After the division, we end up with 100187.5169753 and a remainder of 5.6e-07.