We look at the division of 642915 by 99 
The aim is to understand the frequency of 99 in 642915.

Advancing to step 1:
When dividing 6 by 99, we get 0 with a remainder of 6.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Append the next digit (4) from the dividend to 6 and continue with: 64 / 99

On to step 2:
99 goes into 64 0 times with a remainder of 64.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 64, we end up with 64.
Take the next digit (2) from the dividend and append it to 64, then repeat: 642 / 99

Moving on to step 3:
The number 99 fits into 642 6 times, leaving a remainder of 48.
Put 6 as the next digit of the answer. 
Result so far: 6.0
The remainder is 48 after subtracting 594 from 642.
Append the next digit (9) from the dividend to 48 and continue with: 489 / 99

Let's proceed to step 4:
When dividing 489 by 99, we get 4 with a remainder of 93.
Write down 4 as next digit of the result. 
Result so far: 64.0
If we subtract 396 from 489, we get 93.
Bring next digit (1) of the dividend behind the 93 and repeat the process: 931 / 99

Let's proceed to step 5:
931 divided by 99 is 9 with a remainder of 40.
The next digit of our result is 9. 
Result so far: 649.0
The remainder is 40 after subtracting 891 from 931.
Take the next digit (5) from the dividend and append it to 40, then repeat: 405 / 99

Let's proceed to step 6:
405 divided by 99 is 4 with a remainder of 9.
Use 4 as the next digit of our solution. 
Result so far: 6494.0
If we subtract 396 from 405, we get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Advancing to step 7:
If we divide 90 by 99, we get 0 and a remainder of 90.
Put 0 as the next digit of the answer. 
Result so far: 6494.0
If we take 0 away from 90, we end up with 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 900, and continue the process.

Moving on to step 8:
If we divide 900 by 99, we get 9 and a remainder of 9.
The next digit of our result is 9. 
Result so far: 6494.09
Deduct 891 from 900 and we're left with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Step 9:
When dividing 90 by 99, we get 0 with a remainder of 90.
Record the quotient 0 as the next digit in the result. 
Result so far: 6494.09
Deduct 0 from 90 and we're left with 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 900, and continue the process.

Moving on to step 10:
99 goes into 900 9 times with a remainder of 9.
The number 9 becomes the next digit in our result. 
Result so far: 6494.0909
Deduct 891 from 900 and we're left with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Step 11:
If we divide 90 by 99, we get 0 and a remainder of 90.
Use 0 as the next digit of our solution. 
Result so far: 6494.0909
If we subtract 0 from 90, we get 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 900, and continue the process.

Going ahead to step 12:
When dividing 900 by 99, we get 9 with a remainder of 9.
The number 9 becomes the next digit in our result. 
Result so far: 6494.090909
The remainder is 9 after subtracting 891 from 900.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Moving on to step 13:
99 can be fit into 90 0 times, resulting in a remainder of 90.
Write down 0 as next digit of the result. 
Result so far: 6494.090909
If we take 0 away from 90, we end up with 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 900, and continue the process.

On to step 14:
When dividing 900 by 99, we get 9 with a remainder of 9.
The next digit of our result is 9. 
Result so far: 6494.09090909
If we take 891 away from 900, we end up with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

The final outcome is 6494.09090909, with a leftover of 9e-09.