We look at the division of 900018 by 90 
The aim is to understand the frequency of 90 in 900018.

On to step 1:
When dividing 9 by 90, we get 0 with a remainder of 9.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 9, we end up with 9.
Include the next digit (0) from the dividend after 9, then repeat: 90 / 90

On to step 2:
If we divide 90 by 90, we get 1 and a remainder of 0.
Write down 1 as next digit of the result. 
Result so far: 1.0
Subtracting 90 from 90 leaves us with 0.
Fetch the next digit (0) from the dividend, attach it to 0 and continue: 0 / 90

Going ahead to step 3:
The number 90 fits into 0 0 times, leaving a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 10.0
If we subtract 0 from 0, we get 0.
Take the next digit (0) from the dividend and append it to 0, then repeat: 0 / 90

Moving on to step 4:
When dividing 0 by 90, we get 0 with a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 100.0
Subtracting 0 from 0 leaves us with 0.
Grab the next digit (1) from the dividend, add it to 0, then carry on: 1 / 90

Let's proceed to step 5:
90 can be fit into 1 0 times, resulting in a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 1000.0
Deduct 0 from 1 and we're left with 1.
Take the next digit (8) from the dividend and append it to 1, then repeat: 18 / 90

Let's proceed to step 6:
18 divided by 90 is 0 with a remainder of 18.
The number 0 becomes the next digit in our result. 
Result so far: 10000.0
If we subtract 0 from 18, we get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

On to step 7:
90 goes into 180 2 times with a remainder of 0.
The next digit of our result is 2. 
Result so far: 10000.2
Subtracting 180 from 180 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 8:
90 can be fit into 0 0 times, resulting in a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 10000.2
If we take 0 away from 0, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 9:
90 goes into 0 0 times with a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 10000.2
If we take 0 away from 0, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The quotient of the division is 10000.2, and the remainder is 0.0.