We're dividing 608509 by 90 
The aim is to understand the frequency of 90 in 608509.

Moving on to step 1:
90 can be fit into 6 0 times, resulting in a remainder of 6.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Grab the next digit (0) from the dividend, add it to 6, then carry on: 60 / 90

Let's proceed to step 2:
If we divide 60 by 90, we get 0 and a remainder of 60.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 60 and we're left with 60.
Grab the next digit (8) from the dividend, add it to 60, then carry on: 608 / 90

Going ahead to step 3:
When dividing 608 by 90, we get 6 with a remainder of 68.
Put 6 as the next digit of the answer. 
Result so far: 6.0
If we subtract 540 from 608, we get 68.
Grab the next digit (5) from the dividend, add it to 68, then carry on: 685 / 90

Let's proceed to step 4:
When dividing 685 by 90, we get 7 with a remainder of 55.
Use 7 as the next digit of our solution. 
Result so far: 67.0
Deduct 630 from 685 and we're left with 55.
Append the next digit (0) from the dividend to 55 and continue with: 550 / 90

Advancing to step 5:
The number 90 fits into 550 6 times, leaving a remainder of 10.
The next digit of our result is 6. 
Result so far: 676.0
Subtracting 540 from 550 leaves us with 10.
Include the next digit (9) from the dividend after 10, then repeat: 109 / 90

On to step 6:
90 can be fit into 109 1 times, resulting in a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 6761.0
Deduct 90 from 109 and we're left with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Let's proceed to step 7:
If we divide 190 by 90, we get 2 and a remainder of 10.
The number 2 becomes the next digit in our result. 
Result so far: 6761.2
Subtract 180 from 190 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.

Step 8:
90 can be fit into 100 1 times, resulting in a remainder of 10.
Use 1 as the next digit of our solution. 
Result so far: 6761.21
Subtracting 90 from 100 leaves us 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.

Let's proceed to step 9:
90 goes into 100 1 times with a remainder of 10.
Write down 1 as next digit of the result. 
Result so far: 6761.211
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.

Our division results in 6761.211 with a remaining 0.001.