We're dividing 75161216 by 90 
The aim is to understand the frequency of 90 in 75161216.

Advancing to step 1:
If we divide 7 by 90, we get 0 and a remainder of 7.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 7 leaves us with 7.
Fetch the next digit (5) from the dividend, attach it to 7 and continue: 75 / 90

Moving on to step 2:
90 can be fit into 75 0 times, resulting in a remainder of 75.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 75, we end up with 75.
Fetch the next digit (1) from the dividend, attach it to 75 and continue: 751 / 90

Advancing to step 3:
90 goes into 751 8 times with a remainder of 31.
The next digit of our result is 8. 
Result so far: 8.0
Deduct 720 from 751 and we're left with 31.
Include the next digit (6) from the dividend after 31, then repeat: 316 / 90

Let's proceed to step 4:
If we divide 316 by 90, we get 3 and a remainder of 46.
Write down 3 as next digit of the result. 
Result so far: 83.0
Deduct 270 from 316 and we're left with 46.
Append the next digit (1) from the dividend to 46 and continue with: 461 / 90

Moving on to step 5:
461 divided by 90 is 5 with a remainder of 11.
Put 5 as the next digit of the answer. 
Result so far: 835.0
Subtract 450 from 461 to get 11.
Append the next digit (2) from the dividend to 11 and continue with: 112 / 90

Advancing to step 6:
90 goes into 112 1 times with a remainder of 22.
The number 1 becomes the next digit in our result. 
Result so far: 8351.0
Subtracting 90 from 112 leaves us with 22.
Include the next digit (1) from the dividend after 22, then repeat: 221 / 90

Moving on to step 7:
When dividing 221 by 90, we get 2 with a remainder of 41.
The next digit of our result is 2. 
Result so far: 83512.0
Subtract 180 from 221 to get 41.
Append the next digit (6) from the dividend to 41 and continue with: 416 / 90

Moving on to step 8:
90 can be fit into 416 4 times, resulting in a remainder of 56.
The next digit of our result is 4. 
Result so far: 835124.0
Subtract 360 from 416 to get 56.
Since there are no more digits in the dividend, we add a zero to the remainder making it 560, and continue the process.

On to step 9:
When dividing 560 by 90, we get 6 with a remainder of 20.
Put 6 as the next digit of the answer. 
Result so far: 835124.6
If we subtract 540 from 560, we 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 10:
90 goes into 200 2 times with a remainder of 20.
Write down 2 as next digit of the result. 
Result so far: 835124.62
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.

On to step 11:
The number 90 fits into 200 2 times, leaving a remainder of 20.
Record the quotient 2 as the next digit in the result. 
Result so far: 835124.622
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.

The final result is 835124.622 with a remainder of 0.002.