We're dividing 42453050 by 90 
The aim is to understand the frequency of 90 in 42453050.

On to step 1:
When dividing 4 by 90, we get 0 with a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Fetch the next digit (2) from the dividend, attach it to 4 and continue: 42 / 90

On to step 2:
90 goes into 42 0 times with a remainder of 42.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 42 to get 42.
Take the next digit (4) from the dividend and append it to 42, then repeat: 424 / 90

Step 3:
90 goes into 424 4 times with a remainder of 64.
Put 4 as the next digit of the answer. 
Result so far: 4.0
If we subtract 360 from 424, we get 64.
Include the next digit (5) from the dividend after 64, then repeat: 645 / 90

On to step 4:
If we divide 645 by 90, we get 7 and a remainder of 15.
The number 7 becomes the next digit in our result. 
Result so far: 47.0
The remainder is 15 after subtracting 630 from 645.
Take the next digit (3) from the dividend and append it to 15, then repeat: 153 / 90

Let's proceed to step 5:
90 can be fit into 153 1 times, resulting in a remainder of 63.
Put 1 as the next digit of the answer. 
Result so far: 471.0
The remainder is 63 after subtracting 90 from 153.
Fetch the next digit (0) from the dividend, attach it to 63 and continue: 630 / 90

On to step 6:
630 divided by 90 is 7 with a remainder of 0.
Record the quotient 7 as the next digit in the result. 
Result so far: 4717.0
Deduct 630 from 630 and we're left with 0.
Take the next digit (5) from the dividend and append it to 0, then repeat: 5 / 90

Moving on to step 7:
The number 90 fits into 5 0 times, leaving a remainder of 5.
Record the quotient 0 as the next digit in the result. 
Result so far: 47170.0
Subtracting 0 from 5 leaves us with 5.
Take the next digit (0) from the dividend and append it to 5, then repeat: 50 / 90

Moving on to step 8:
The number 90 fits into 50 0 times, leaving a remainder of 50.
The number 0 becomes the next digit in our result. 
Result so far: 471700.0
Deduct 0 from 50 and we're left with 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Moving on to step 9:
90 can be fit into 500 5 times, resulting in a remainder of 50.
The next digit of our result is 5. 
Result so far: 471700.5
Subtracting 450 from 500 leaves us with 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Moving on to step 10:
500 divided by 90 is 5 with a remainder of 50.
Use 5 as the next digit of our solution. 
Result so far: 471700.55
Subtract 450 from 500 to get 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Our division results in 471700.55 with a remaining 0.05.