We look at the division of 637155 by 90 
The aim is to understand the frequency of 90 in 637155.

Advancing to step 1:
6 divided by 90 is 0 with a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Grab the next digit (3) from the dividend, add it to 6, then carry on: 63 / 90

Moving on to step 2:
90 goes into 63 0 times with a remainder of 63.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 63 leaves us with 63.
Grab the next digit (7) from the dividend, add it to 63, then carry on: 637 / 90

Step 3:
637 divided by 90 is 7 with a remainder of 7.
Use 7 as the next digit of our solution. 
Result so far: 7.0
Subtract 630 from 637 to get 7.
Grab the next digit (1) from the dividend, add it to 7, then carry on: 71 / 90

Moving on to step 4:
90 goes into 71 0 times with a remainder of 71.
Write down 0 as next digit of the result. 
Result so far: 70.0
The remainder is 71 after subtracting 0 from 71.
Include the next digit (5) from the dividend after 71, then repeat: 715 / 90

Moving on to step 5:
90 goes into 715 7 times with a remainder of 85.
Use 7 as the next digit of our solution. 
Result so far: 707.0
Subtract 630 from 715 to get 85.
Grab the next digit (5) from the dividend, add it to 85, then carry on: 855 / 90

Going ahead to step 6:
The number 90 fits into 855 9 times, leaving a remainder of 45.
The next digit of our result is 9. 
Result so far: 7079.0
Deduct 810 from 855 and we're left with 45.
Since there are no more digits in the dividend, we add a zero to the remainder making it 450, and continue the process.

Let's proceed to step 7:
90 goes into 450 5 times with a remainder of 0.
Use 5 as the next digit of our solution. 
Result so far: 7079.5
The remainder is 0 after subtracting 450 from 450.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Step 8:
0 divided by 90 is 0 with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 7079.5
If we take 0 away from 0, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 9:
90 can be fit into 0 0 times, resulting in a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 7079.5
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final result is 7079.5 with a remainder of 0.0.