We're dividing 480901 by 90 
The aim is to understand the frequency of 90 in 480901.

On to step 1:
If we divide 4 by 90, we get 0 and a remainder of 4.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 4 to get 4.
Bring next digit (8) of the dividend behind the 4 and repeat the process: 48 / 90

Let's proceed to step 2:
The number 90 fits into 48 0 times, leaving a remainder of 48.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 48 leaves us with 48.
Append the next digit (0) from the dividend to 48 and continue with: 480 / 90

Going ahead to step 3:
480 divided by 90 is 5 with a remainder of 30.
Use 5 as the next digit of our solution. 
Result so far: 5.0
The remainder is 30 after subtracting 450 from 480.
Fetch the next digit (9) from the dividend, attach it to 30 and continue: 309 / 90

Going ahead to step 4:
When dividing 309 by 90, we get 3 with a remainder of 39.
Write down 3 as next digit of the result. 
Result so far: 53.0
Deduct 270 from 309 and we're left with 39.
Grab the next digit (0) from the dividend, add it to 39, then carry on: 390 / 90

Advancing to step 5:
If we divide 390 by 90, we get 4 and a remainder of 30.
The number 4 becomes the next digit in our result. 
Result so far: 534.0
Subtract 360 from 390 to get 30.
Bring next digit (1) of the dividend behind the 30 and repeat the process: 301 / 90

Moving on to step 6:
90 can be fit into 301 3 times, resulting in a remainder of 31.
The next digit of our result is 3. 
Result so far: 5343.0
Subtract 270 from 301 to get 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

On to step 7:
If we divide 310 by 90, we get 3 and a remainder of 40.
The next digit of our result is 3. 
Result so far: 5343.3
Subtracting 270 from 310 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.

On to step 8:
The number 90 fits into 400 4 times, leaving a remainder of 40.
Record the quotient 4 as the next digit in the result. 
Result so far: 5343.34
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.

Going ahead to step 9:
The number 90 fits into 400 4 times, leaving a remainder of 40.
Use 4 as the next digit of our solution. 
Result so far: 5343.344
If we take 360 away from 400, we end up 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 outcome is 5343.344, with a leftover of 0.004.