Let's divide 463591 by 90
The aim is to understand the frequency of 90 in 463591.

Advancing to step 1:
If we divide 4 by 90, we get 0 and a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 4, we get 4.
Take the next digit (6) from the dividend and append it to 4, then repeat: 46 / 90

Step 2:
46 divided by 90 is 0 with a remainder of 46.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 46 after subtracting 0 from 46.
Bring next digit (3) of the dividend behind the 46 and repeat the process: 463 / 90

Going ahead to step 3:
90 can be fit into 463 5 times, resulting in a remainder of 13.
The next digit of our result is 5. 
Result so far: 5.0
The remainder is 13 after subtracting 450 from 463.
Append the next digit (5) from the dividend to 13 and continue with: 135 / 90

Advancing to step 4:
When dividing 135 by 90, we get 1 with a remainder of 45.
Write down 1 as next digit of the result. 
Result so far: 51.0
Deduct 90 from 135 and we're left with 45.
Include the next digit (9) from the dividend after 45, then repeat: 459 / 90

Step 5:
90 goes into 459 5 times with a remainder of 9.
Use 5 as the next digit of our solution. 
Result so far: 515.0
If we take 450 away from 459, we end up with 9.
Take the next digit (1) from the dividend and append it to 9, then repeat: 91 / 90

Let's proceed to step 6:
The number 90 fits into 91 1 times, leaving a remainder of 1.
The number 1 becomes the next digit in our result. 
Result so far: 5151.0
Deduct 90 from 91 and we're left with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Advancing to step 7:
The number 90 fits into 10 0 times, leaving a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 5151.0
Subtract 0 from 10 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 8:
If we divide 100 by 90, we get 1 and a remainder of 10.
Record the quotient 1 as the next digit in the result. 
Result so far: 5151.01
If we subtract 90 from 100, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 9:
The number 90 fits into 100 1 times, leaving a remainder of 10.
The number 1 becomes the next digit in our result. 
Result so far: 5151.011
Deduct 90 from 100 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

The final outcome is 5151.011, with a leftover of 0.001.