We're dividing 83907566 by 643 
The aim is to understand the frequency of 643 in 83907566.

Going ahead to step 1:
When dividing 8 by 643, we get 0 with a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Fetch the next digit (3) from the dividend, attach it to 8 and continue: 83 / 643

Advancing to step 2:
If we divide 83 by 643, we get 0 and a remainder of 83.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 83, we end up with 83.
Grab the next digit (9) from the dividend, add it to 83, then carry on: 839 / 643

Let's proceed to step 3:
839 divided by 643 is 1 with a remainder of 196.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Deduct 643 from 839 and we're left with 196.
Take the next digit (0) from the dividend and append it to 196, then repeat: 1960 / 643

Let's proceed to step 4:
The number 643 fits into 1960 3 times, leaving a remainder of 31.
Use 3 as the next digit of our solution. 
Result so far: 13.0
The remainder is 31 after subtracting 1929 from 1960.
Take the next digit (7) from the dividend and append it to 31, then repeat: 317 / 643

Let's proceed to step 5:
643 goes into 317 0 times with a remainder of 317.
Write down 0 as next digit of the result. 
Result so far: 130.0
Deduct 0 from 317 and we're left with 317.
Fetch the next digit (5) from the dividend, attach it to 317 and continue: 3175 / 643

Step 6:
The number 643 fits into 3175 4 times, leaving a remainder of 603.
Record the quotient 4 as the next digit in the result. 
Result so far: 1304.0
The remainder is 603 after subtracting 2572 from 3175.
Include the next digit (6) from the dividend after 603, then repeat: 6036 / 643

Advancing to step 7:
6036 divided by 643 is 9 with a remainder of 249.
The next digit of our result is 9. 
Result so far: 13049.0
If we take 5787 away from 6036, we end up with 249.
Include the next digit (6) from the dividend after 249, then repeat: 2496 / 643

Moving on to step 8:
643 goes into 2496 3 times with a remainder of 567.
Put 3 as the next digit of the answer. 
Result so far: 130493.0
Deduct 1929 from 2496 and we're left with 567.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5670, and continue the process.

Step 9:
The number 643 fits into 5670 8 times, leaving a remainder of 526.
Write down 8 as next digit of the result. 
Result so far: 130493.8
Subtracting 5144 from 5670 leaves us with 526.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5260, and continue the process.

Step 10:
When dividing 5260 by 643, we get 8 with a remainder of 116.
Record the quotient 8 as the next digit in the result. 
Result so far: 130493.88
Deduct 5144 from 5260 and we're left with 116.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1160, and continue the process.

In conclusion, the division gives 130493.88 with a balance of 0.116.