We're dividing 356369 by 90 
The aim is to understand the frequency of 90 in 356369.

Let's proceed to step 1:
If we divide 3 by 90, we get 0 and a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Grab the next digit (5) from the dividend, add it to 3, then carry on: 35 / 90

On to step 2:
90 goes into 35 0 times with a remainder of 35.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 35 after subtracting 0 from 35.
Include the next digit (6) from the dividend after 35, then repeat: 356 / 90

Advancing to step 3:
If we divide 356 by 90, we get 3 and a remainder of 86.
The next digit of our result is 3. 
Result so far: 3.0
If we subtract 270 from 356, we get 86.
Take the next digit (3) from the dividend and append it to 86, then repeat: 863 / 90

Let's proceed to step 4:
The number 90 fits into 863 9 times, leaving a remainder of 53.
Write down 9 as next digit of the result. 
Result so far: 39.0
If we take 810 away from 863, we end up with 53.
Include the next digit (6) from the dividend after 53, then repeat: 536 / 90

On to step 5:
90 can be fit into 536 5 times, resulting in a remainder of 86.
Record the quotient 5 as the next digit in the result. 
Result so far: 395.0
Subtract 450 from 536 to get 86.
Grab the next digit (9) from the dividend, add it to 86, then carry on: 869 / 90

Going ahead to step 6:
If we divide 869 by 90, we get 9 and a remainder of 59.
Use 9 as the next digit of our solution. 
Result so far: 3959.0
Deduct 810 from 869 and we're left with 59.
Since there are no more digits in the dividend, we add a zero to the remainder making it 590, and continue the process.

Advancing to step 7:
The number 90 fits into 590 6 times, leaving a remainder of 50.
Record the quotient 6 as the next digit in the result. 
Result so far: 3959.6
The remainder is 50 after subtracting 540 from 590.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Let's proceed to step 8:
90 can be fit into 500 5 times, resulting in a remainder of 50.
The next digit of our result is 5. 
Result so far: 3959.65
Subtract 450 from 500 to get 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Let's proceed to step 9:
500 divided by 90 is 5 with a remainder of 50.
Record the quotient 5 as the next digit in the result. 
Result so far: 3959.655
Subtracting 450 from 500 leaves us with 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

After the division, we end up with 3959.655 and a remainder of 0.005.