We look at the division of 810754 by 90 
The aim is to understand the frequency of 90 in 810754.

Going ahead to step 1:
90 goes into 8 0 times with a remainder of 8.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Include the next digit (1) from the dividend after 8, then repeat: 81 / 90

Going ahead to step 2:
When dividing 81 by 90, we get 0 with a remainder of 81.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 81 to get 81.
Take the next digit (0) from the dividend and append it to 81, then repeat: 810 / 90

Going ahead to step 3:
810 divided by 90 is 9 with a remainder of 0.
The number 9 becomes the next digit in our result. 
Result so far: 9.0
Subtract 810 from 810 to get 0.
Include the next digit (7) from the dividend after 0, then repeat: 7 / 90

Step 4:
7 divided by 90 is 0 with a remainder of 7.
Put 0 as the next digit of the answer. 
Result so far: 90.0
Deduct 0 from 7 and we're left with 7.
Take the next digit (5) from the dividend and append it to 7, then repeat: 75 / 90

Let's proceed to step 5:
The number 90 fits into 75 0 times, leaving a remainder of 75.
The number 0 becomes the next digit in our result. 
Result so far: 900.0
If we subtract 0 from 75, we get 75.
Take the next digit (4) from the dividend and append it to 75, then repeat: 754 / 90

Let's proceed to step 6:
The number 90 fits into 754 8 times, leaving a remainder of 34.
Use 8 as the next digit of our solution. 
Result so far: 9008.0
Subtracting 720 from 754 leaves us with 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

Advancing to step 7:
90 can be fit into 340 3 times, resulting in a remainder of 70.
The number 3 becomes the next digit in our result. 
Result so far: 9008.3
If we take 270 away from 340, 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.

On to step 8:
90 goes into 700 7 times with a remainder of 70.
Write down 7 as next digit of the result. 
Result so far: 9008.37
The remainder is 70 after subtracting 630 from 700.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

On to step 9:
When dividing 700 by 90, we get 7 with a remainder of 70.
Write down 7 as next digit of the result. 
Result so far: 9008.377
If we subtract 630 from 700, we get 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

The final result is 9008.377 with a remainder of 0.007.