We look at the division of 518052 by 90 
The aim is to understand the frequency of 90 in 518052.

Going ahead to step 1:
When dividing 5 by 90, we get 0 with a remainder of 5.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 5 leaves us with 5.
Grab the next digit (1) from the dividend, add it to 5, then carry on: 51 / 90

Step 2:
90 goes into 51 0 times with a remainder of 51.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 51 after subtracting 0 from 51.
Bring next digit (8) of the dividend behind the 51 and repeat the process: 518 / 90

Going ahead to step 3:
90 goes into 518 5 times with a remainder of 68.
Put 5 as the next digit of the answer. 
Result so far: 5.0
The remainder is 68 after subtracting 450 from 518.
Take the next digit (0) from the dividend and append it to 68, then repeat: 680 / 90

Advancing to step 4:
The number 90 fits into 680 7 times, leaving a remainder of 50.
Use 7 as the next digit of our solution. 
Result so far: 57.0
The remainder is 50 after subtracting 630 from 680.
Fetch the next digit (5) from the dividend, attach it to 50 and continue: 505 / 90

Moving on to step 5:
90 can be fit into 505 5 times, resulting in a remainder of 55.
Record the quotient 5 as the next digit in the result. 
Result so far: 575.0
If we subtract 450 from 505, we get 55.
Take the next digit (2) from the dividend and append it to 55, then repeat: 552 / 90

Advancing to step 6:
552 divided by 90 is 6 with a remainder of 12.
The number 6 becomes the next digit in our result. 
Result so far: 5756.0
If we take 540 away from 552, we end up with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Moving on to step 7:
90 can be fit into 120 1 times, resulting in a remainder of 30.
Write down 1 as next digit of the result. 
Result so far: 5756.1
Deduct 90 from 120 and we're left with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Step 8:
If we divide 300 by 90, we get 3 and a remainder of 30.
The next digit of our result is 3. 
Result so far: 5756.13
If we subtract 270 from 300, we get 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

On to step 9:
90 can be fit into 300 3 times, resulting in a remainder of 30.
Record the quotient 3 as the next digit in the result. 
Result so far: 5756.133
Subtracting 270 from 300 leaves us with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

The quotient of the division is 5756.133, and the remainder is 0.003.