918821 divided by 90 
The aim is to understand the frequency of 90 in 918821.

Going ahead to step 1:
If we divide 9 by 90, we get 0 and a remainder of 9.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 9, we end up with 9.
Append the next digit (1) from the dividend to 9 and continue with: 91 / 90

Moving on to step 2:
90 goes into 91 1 times with a remainder of 1.
The next digit of our result is 1. 
Result so far: 1.0
Subtracting 90 from 91 leaves us with 1.
Include the next digit (8) from the dividend after 1, then repeat: 18 / 90

Advancing to step 3:
18 divided by 90 is 0 with a remainder of 18.
Put 0 as the next digit of the answer. 
Result so far: 10.0
If we subtract 0 from 18, we get 18.
Take the next digit (8) from the dividend and append it to 18, then repeat: 188 / 90

On to step 4:
If we divide 188 by 90, we get 2 and a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 102.0
If we subtract 180 from 188, we get 8.
Fetch the next digit (2) from the dividend, attach it to 8 and continue: 82 / 90

Going ahead to step 5:
90 goes into 82 0 times with a remainder of 82.
Use 0 as the next digit of our solution. 
Result so far: 1020.0
Subtracting 0 from 82 leaves us with 82.
Grab the next digit (1) from the dividend, add it to 82, then carry on: 821 / 90

On to step 6:
90 goes into 821 9 times with a remainder of 11.
The number 9 becomes the next digit in our result. 
Result so far: 10209.0
If we take 810 away from 821, we end up with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 7:
When dividing 110 by 90, we get 1 with a remainder of 20.
The number 1 becomes the next digit in our result. 
Result so far: 10209.1
The remainder is 20 after subtracting 90 from 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Moving on to step 8:
When dividing 200 by 90, we get 2 with a remainder of 20.
Use 2 as the next digit of our solution. 
Result so far: 10209.12
Subtracting 180 from 200 leaves us with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Going ahead to step 9:
90 goes into 200 2 times with a remainder of 20.
Use 2 as the next digit of our solution. 
Result so far: 10209.122
The remainder is 20 after subtracting 180 from 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

The final outcome is 10209.122, with a leftover of 0.002.