Let's divide 878497 by 90
The aim is to understand the frequency of 90 in 878497.

Moving on to step 1:
90 goes into 8 0 times with a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 8 after subtracting 0 from 8.
Take the next digit (7) from the dividend and append it to 8, then repeat: 87 / 90

Moving on to step 2:
87 divided by 90 is 0 with a remainder of 87.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 87 after subtracting 0 from 87.
Include the next digit (8) from the dividend after 87, then repeat: 878 / 90

Let's proceed to step 3:
When dividing 878 by 90, we get 9 with a remainder of 68.
The next digit of our result is 9. 
Result so far: 9.0
If we subtract 810 from 878, we get 68.
Bring next digit (4) of the dividend behind the 68 and repeat the process: 684 / 90

Step 4:
684 divided by 90 is 7 with a remainder of 54.
Use 7 as the next digit of our solution. 
Result so far: 97.0
The remainder is 54 after subtracting 630 from 684.
Take the next digit (9) from the dividend and append it to 54, then repeat: 549 / 90

On to step 5:
90 goes into 549 6 times with a remainder of 9.
Use 6 as the next digit of our solution. 
Result so far: 976.0
If we subtract 540 from 549, we get 9.
Take the next digit (7) from the dividend and append it to 9, then repeat: 97 / 90

On to step 6:
The number 90 fits into 97 1 times, leaving a remainder of 7.
Use 1 as the next digit of our solution. 
Result so far: 9761.0
Subtract 90 from 97 to get 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Let's proceed to step 7:
90 goes into 70 0 times with a remainder of 70.
Record the quotient 0 as the next digit in the result. 
Result so far: 9761.0
The remainder is 70 after subtracting 0 from 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Step 8:
90 can be fit into 700 7 times, resulting in a remainder of 70.
Put 7 as the next digit of the answer. 
Result so far: 9761.07
Deduct 630 from 700 and we're left with 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Let's proceed to step 9:
90 can be fit into 700 7 times, resulting in a remainder of 70.
The number 7 becomes the next digit in our result. 
Result so far: 9761.077
If we take 630 away from 700, we end up with 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Our division results in 9761.077 with a remaining 0.007.