We look at the division of 243810 by 90 
The aim is to understand the frequency of 90 in 243810.

Step 1:
The number 90 fits into 2 0 times, leaving a remainder of 2.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 2 leaves us with 2.
Bring next digit (4) of the dividend behind the 2 and repeat the process: 24 / 90

Step 2:
90 goes into 24 0 times with a remainder of 24.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 24 to get 24.
Fetch the next digit (3) from the dividend, attach it to 24 and continue: 243 / 90

Advancing to step 3:
243 divided by 90 is 2 with a remainder of 63.
Use 2 as the next digit of our solution. 
Result so far: 2.0
Subtract 180 from 243 to get 63.
Bring next digit (8) of the dividend behind the 63 and repeat the process: 638 / 90

Moving on to step 4:
The number 90 fits into 638 7 times, leaving a remainder of 8.
The number 7 becomes the next digit in our result. 
Result so far: 27.0
The remainder is 8 after subtracting 630 from 638.
Grab the next digit (1) from the dividend, add it to 8, then carry on: 81 / 90

Advancing to step 5:
When dividing 81 by 90, we get 0 with a remainder of 81.
Put 0 as the next digit of the answer. 
Result so far: 270.0
Subtracting 0 from 81 leaves us with 81.
Append the next digit (0) from the dividend to 81 and continue with: 810 / 90

Let's proceed to step 6:
90 can be fit into 810 9 times, resulting in a remainder of 0.
Use 9 as the next digit of our solution. 
Result so far: 2709.0
Deduct 810 from 810 and we're left 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 7:
90 goes into 0 0 times with a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 2709.0
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Going ahead to step 8:
If we divide 0 by 90, we get 0 and a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 2709.0
Deduct 0 from 0 and we're left 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 2709.0 with a remainder of 0.0.