10011856 divided by 90 
The aim is to understand the frequency of 90 in 10011856.

Step 1:
The number 90 fits into 1 0 times, leaving a remainder of 1.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 1 after subtracting 0 from 1.
Grab the next digit (0) from the dividend, add it to 1, then carry on: 10 / 90

Advancing to step 2:
10 divided by 90 is 0 with a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 10, we get 10.
Append the next digit (0) from the dividend to 10 and continue with: 100 / 90

Step 3:
When dividing 100 by 90, we get 1 with a remainder of 10.
The next digit of our result is 1. 
Result so far: 1.0
Subtract 90 from 100 to get 10.
Bring next digit (1) of the dividend behind the 10 and repeat the process: 101 / 90

Step 4:
90 can be fit into 101 1 times, resulting in a remainder of 11.
The number 1 becomes the next digit in our result. 
Result so far: 11.0
Deduct 90 from 101 and we're left with 11.
Include the next digit (1) from the dividend after 11, then repeat: 111 / 90

Advancing to step 5:
If we divide 111 by 90, we get 1 and a remainder of 21.
Write down 1 as next digit of the result. 
Result so far: 111.0
Subtracting 90 from 111 leaves us with 21.
Take the next digit (8) from the dividend and append it to 21, then repeat: 218 / 90

Let's proceed to step 6:
The number 90 fits into 218 2 times, leaving a remainder of 38.
Use 2 as the next digit of our solution. 
Result so far: 1112.0
Subtract 180 from 218 to get 38.
Append the next digit (5) from the dividend to 38 and continue with: 385 / 90

Let's proceed to step 7:
90 can be fit into 385 4 times, resulting in a remainder of 25.
Record the quotient 4 as the next digit in the result. 
Result so far: 11124.0
If we take 360 away from 385, we end up with 25.
Include the next digit (6) from the dividend after 25, then repeat: 256 / 90

Moving on to step 8:
256 divided by 90 is 2 with a remainder of 76.
Use 2 as the next digit of our solution. 
Result so far: 111242.0
Subtract 180 from 256 to get 76.
Since there are no more digits in the dividend, we add a zero to the remainder making it 760, and continue the process.

Going ahead to step 9:
90 can be fit into 760 8 times, resulting in a remainder of 40.
Use 8 as the next digit of our solution. 
Result so far: 111242.8
Subtracting 720 from 760 leaves us with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Advancing to step 10:
90 can be fit into 400 4 times, resulting in a remainder of 40.
Put 4 as the next digit of the answer. 
Result so far: 111242.84
Subtract 360 from 400 to get 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Step 11:
When dividing 400 by 90, we get 4 with a remainder of 40.
The number 4 becomes the next digit in our result. 
Result so far: 111242.844
Deduct 360 from 400 and we're left with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

The final result is 111242.844 with a remainder of 0.004.