64878530 divided by 643 
The aim is to understand the frequency of 643 in 64878530.

Let's proceed to step 1:
If we divide 6 by 643, we get 0 and a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Take the next digit (4) from the dividend and append it to 6, then repeat: 64 / 643

Going ahead to step 2:
643 can be fit into 64 0 times, resulting in a remainder of 64.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 64, we end up with 64.
Grab the next digit (8) from the dividend, add it to 64, then carry on: 648 / 643

Moving on to step 3:
643 goes into 648 1 times with a remainder of 5.
Write down 1 as next digit of the result. 
Result so far: 1.0
The remainder is 5 after subtracting 643 from 648.
Append the next digit (7) from the dividend to 5 and continue with: 57 / 643

Going ahead to step 4:
643 can be fit into 57 0 times, resulting in a remainder of 57.
Use 0 as the next digit of our solution. 
Result so far: 10.0
If we subtract 0 from 57, we get 57.
Bring next digit (8) of the dividend behind the 57 and repeat the process: 578 / 643

Step 5:
578 divided by 643 is 0 with a remainder of 578.
The next digit of our result is 0. 
Result so far: 100.0
Subtract 0 from 578 to get 578.
Bring next digit (5) of the dividend behind the 578 and repeat the process: 5785 / 643

Moving on to step 6:
When dividing 5785 by 643, we get 8 with a remainder of 641.
Put 8 as the next digit of the answer. 
Result so far: 1008.0
Subtracting 5144 from 5785 leaves us with 641.
Fetch the next digit (3) from the dividend, attach it to 641 and continue: 6413 / 643

Step 7:
The number 643 fits into 6413 9 times, leaving a remainder of 626.
The next digit of our result is 9. 
Result so far: 10089.0
Subtracting 5787 from 6413 leaves us with 626.
Fetch the next digit (0) from the dividend, attach it to 626 and continue: 6260 / 643

Moving on to step 8:
When dividing 6260 by 643, we get 9 with a remainder of 473.
The next digit of our result is 9. 
Result so far: 100899.0
Deduct 5787 from 6260 and we're left with 473.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4730, and continue the process.

Going ahead to step 9:
If we divide 4730 by 643, we get 7 and a remainder of 229.
The number 7 becomes the next digit in our result. 
Result so far: 100899.7
The remainder is 229 after subtracting 4501 from 4730.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2290, and continue the process.

Let's proceed to step 10:
643 goes into 2290 3 times with a remainder of 361.
Put 3 as the next digit of the answer. 
Result so far: 100899.73
The remainder is 361 after subtracting 1929 from 2290.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3610, and continue the process.

On to step 11:
If we divide 3610 by 643, we get 5 and a remainder of 395.
Put 5 as the next digit of the answer. 
Result so far: 100899.735
The remainder is 395 after subtracting 3215 from 3610.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3950, and continue the process.

Step 12:
When dividing 3950 by 643, we get 6 with a remainder of 92.
The number 6 becomes the next digit in our result. 
Result so far: 100899.7356
If we take 3858 away from 3950, we end up with 92.
Since there are no more digits in the dividend, we add a zero to the remainder making it 920, and continue the process.

Going ahead to step 13:
920 divided by 643 is 1 with a remainder of 277.
Put 1 as the next digit of the answer. 
Result so far: 100899.73561
Deduct 643 from 920 and we're left with 277.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2770, and continue the process.

Step 14:
643 goes into 2770 4 times with a remainder of 198.
The number 4 becomes the next digit in our result. 
Result so far: 100899.735614
The remainder is 198 after subtracting 2572 from 2770.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1980, and continue the process.

Advancing to step 15:
If we divide 1980 by 643, we get 3 and a remainder of 51.
The next digit of our result is 3. 
Result so far: 100899.7356143
Deduct 1929 from 1980 and we're left with 51.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

Moving on to step 16:
510 divided by 643 is 0 with a remainder of 510.
Put 0 as the next digit of the answer. 
Result so far: 100899.7356143
If we take 0 away from 510, we end up with 510.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5100, and continue the process.

In conclusion, the division gives 100899.7356143 with a balance of 5.1e-07.