We look at the division of 261313 by 90 
The aim is to understand the frequency of 90 in 261313.

Let's proceed to step 1:
90 can be fit into 2 0 times, resulting in a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 2, we get 2.
Include the next digit (6) from the dividend after 2, then repeat: 26 / 90

Going ahead to step 2:
When dividing 26 by 90, we get 0 with a remainder of 26.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 26, we get 26.
Take the next digit (1) from the dividend and append it to 26, then repeat: 261 / 90

Advancing to step 3:
The number 90 fits into 261 2 times, leaving a remainder of 81.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
Deduct 180 from 261 and we're left with 81.
Bring next digit (3) of the dividend behind the 81 and repeat the process: 813 / 90

Advancing to step 4:
If we divide 813 by 90, we get 9 and a remainder of 3.
The next digit of our result is 9. 
Result so far: 29.0
Subtracting 810 from 813 leaves us with 3.
Fetch the next digit (1) from the dividend, attach it to 3 and continue: 31 / 90

Moving on to step 5:
31 divided by 90 is 0 with a remainder of 31.
Use 0 as the next digit of our solution. 
Result so far: 290.0
Deduct 0 from 31 and we're left with 31.
Take the next digit (3) from the dividend and append it to 31, then repeat: 313 / 90

Advancing to step 6:
The number 90 fits into 313 3 times, leaving a remainder of 43.
Record the quotient 3 as the next digit in the result. 
Result so far: 2903.0
Subtracting 270 from 313 leaves us with 43.
Since there are no more digits in the dividend, we add a zero to the remainder making it 430, and continue the process.

Advancing to step 7:
430 divided by 90 is 4 with a remainder of 70.
The next digit of our result is 4. 
Result so far: 2903.4
Deduct 360 from 430 and we're left with 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Step 8:
When dividing 700 by 90, we get 7 with a remainder of 70.
The number 7 becomes the next digit in our result. 
Result so far: 2903.47
Deduct 630 from 700 and we're left with 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

On to step 9:
700 divided by 90 is 7 with a remainder of 70.
Write down 7 as next digit of the result. 
Result so far: 2903.477
If we subtract 630 from 700, we get 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

The quotient of the division is 2903.477, and the remainder is 0.007.