609131 ÷ 90 
The aim is to understand the frequency of 90 in 609131.

Let's proceed to step 1:
6 divided by 90 is 0 with a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Fetch the next digit (0) from the dividend, attach it to 6 and continue: 60 / 90

Advancing to step 2:
If we divide 60 by 90, we get 0 and a remainder of 60.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 60 after subtracting 0 from 60.
Fetch the next digit (9) from the dividend, attach it to 60 and continue: 609 / 90

Step 3:
609 divided by 90 is 6 with a remainder of 69.
Write down 6 as next digit of the result. 
Result so far: 6.0
The remainder is 69 after subtracting 540 from 609.
Include the next digit (1) from the dividend after 69, then repeat: 691 / 90

Going ahead to step 4:
If we divide 691 by 90, we get 7 and a remainder of 61.
Write down 7 as next digit of the result. 
Result so far: 67.0
If we subtract 630 from 691, we get 61.
Fetch the next digit (3) from the dividend, attach it to 61 and continue: 613 / 90

Moving on to step 5:
90 goes into 613 6 times with a remainder of 73.
Use 6 as the next digit of our solution. 
Result so far: 676.0
If we subtract 540 from 613, we get 73.
Take the next digit (1) from the dividend and append it to 73, then repeat: 731 / 90

Moving on to step 6:
If we divide 731 by 90, we get 8 and a remainder of 11.
Use 8 as the next digit of our solution. 
Result so far: 6768.0
If we subtract 720 from 731, we get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Step 7:
When dividing 110 by 90, we get 1 with a remainder of 20.
Put 1 as the next digit of the answer. 
Result so far: 6768.1
If we take 90 away from 110, we end up with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Going ahead to step 8:
When dividing 200 by 90, we get 2 with a remainder of 20.
Write down 2 as next digit of the result. 
Result so far: 6768.12
Subtract 180 from 200 to get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Step 9:
If we divide 200 by 90, we get 2 and a remainder of 20.
The number 2 becomes the next digit in our result. 
Result so far: 6768.122
The remainder is 20 after subtracting 180 from 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

After the division, we end up with 6768.122 and a remainder of 0.002.