We divide 23515 by 90
The aim is to understand the frequency of 90 in 23515.

Let's proceed to step 1:
The number 90 fits into 2 0 times, leaving a remainder of 2.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 2 leaves us with 2.
Grab the next digit (3) from the dividend, add it to 2, then carry on: 23 / 90

Advancing to step 2:
23 divided by 90 is 0 with a remainder of 23.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 23 and we're left with 23.
Take the next digit (5) from the dividend and append it to 23, then repeat: 235 / 90

On to step 3:
If we divide 235 by 90, we get 2 and a remainder of 55.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
If we take 180 away from 235, we end up with 55.
Bring next digit (1) of the dividend behind the 55 and repeat the process: 551 / 90

Moving on to step 4:
90 goes into 551 6 times with a remainder of 11.
Put 6 as the next digit of the answer. 
Result so far: 26.0
If we take 540 away from 551, we end up with 11.
Include the next digit (5) from the dividend after 11, then repeat: 115 / 90

Going ahead to step 5:
90 goes into 115 1 times with a remainder of 25.
Put 1 as the next digit of the answer. 
Result so far: 261.0
Deduct 90 from 115 and we're left with 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

Moving on to step 6:
250 divided by 90 is 2 with a remainder of 70.
The next digit of our result is 2. 
Result so far: 261.2
Deduct 180 from 250 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.

Advancing to step 7:
700 divided by 90 is 7 with a remainder of 70.
Record the quotient 7 as the next digit in the result. 
Result so far: 261.27
Subtracting 630 from 700 leaves us 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.

Going ahead to step 8:
The number 90 fits into 700 7 times, leaving a remainder of 70.
Write down 7 as next digit of the result. 
Result so far: 261.277
Subtracting 630 from 700 leaves us 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.

After the division, we end up with 261.277 and a remainder of 0.007.