512250 ÷ 90 
The aim is to understand the frequency of 90 in 512250.

Advancing to step 1:
The number 90 fits into 5 0 times, leaving a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 5 to get 5.
Append the next digit (1) from the dividend to 5 and continue with: 51 / 90

Moving on to step 2:
When dividing 51 by 90, we get 0 with a remainder of 51.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 51 leaves us with 51.
Bring next digit (2) of the dividend behind the 51 and repeat the process: 512 / 90

Advancing to step 3:
When dividing 512 by 90, we get 5 with a remainder of 62.
Put 5 as the next digit of the answer. 
Result so far: 5.0
The remainder is 62 after subtracting 450 from 512.
Grab the next digit (2) from the dividend, add it to 62, then carry on: 622 / 90

Advancing to step 4:
The number 90 fits into 622 6 times, leaving a remainder of 82.
Write down 6 as next digit of the result. 
Result so far: 56.0
Deduct 540 from 622 and we're left with 82.
Include the next digit (5) from the dividend after 82, then repeat: 825 / 90

Advancing to step 5:
90 can be fit into 825 9 times, resulting in a remainder of 15.
Use 9 as the next digit of our solution. 
Result so far: 569.0
Subtracting 810 from 825 leaves us with 15.
Take the next digit (0) from the dividend and append it to 15, then repeat: 150 / 90

On to step 6:
90 goes into 150 1 times with a remainder of 60.
Use 1 as the next digit of our solution. 
Result so far: 5691.0
Subtracting 90 from 150 leaves us with 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Advancing to step 7:
600 divided by 90 is 6 with a remainder of 60.
Record the quotient 6 as the next digit in the result. 
Result so far: 5691.6
Subtract 540 from 600 to get 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

On to step 8:
600 divided by 90 is 6 with a remainder of 60.
The number 6 becomes the next digit in our result. 
Result so far: 5691.66
The remainder is 60 after subtracting 540 from 600.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

The final outcome is 5691.66, with a leftover of 0.06.