517954 divided by 90 
The aim is to understand the frequency of 90 in 517954.

Advancing to step 1:
5 divided by 90 is 0 with a remainder of 5.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 5 and we're left with 5.
Include the next digit (1) from the dividend after 5, then repeat: 51 / 90

Advancing to step 2:
90 can be fit into 51 0 times, resulting in a remainder of 51.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 51, we get 51.
Append the next digit (7) from the dividend to 51 and continue with: 517 / 90

Advancing to step 3:
The number 90 fits into 517 5 times, leaving a remainder of 67.
The next digit of our result is 5. 
Result so far: 5.0
Subtracting 450 from 517 leaves us with 67.
Take the next digit (9) from the dividend and append it to 67, then repeat: 679 / 90

Advancing to step 4:
90 goes into 679 7 times with a remainder of 49.
Record the quotient 7 as the next digit in the result. 
Result so far: 57.0
The remainder is 49 after subtracting 630 from 679.
Append the next digit (5) from the dividend to 49 and continue with: 495 / 90

Moving on to step 5:
If we divide 495 by 90, we get 5 and a remainder of 45.
Put 5 as the next digit of the answer. 
Result so far: 575.0
Deduct 450 from 495 and we're left with 45.
Grab the next digit (4) from the dividend, add it to 45, then carry on: 454 / 90

Moving on to step 6:
The number 90 fits into 454 5 times, leaving a remainder of 4.
Put 5 as the next digit of the answer. 
Result so far: 5755.0
Subtract 450 from 454 to get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Advancing to step 7:
90 can be fit into 40 0 times, resulting in a remainder of 40.
The next digit of our result is 0. 
Result so far: 5755.0
If we take 0 away from 40, we end up with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

On to step 8:
90 can be fit into 400 4 times, resulting in a remainder of 40.
Put 4 as the next digit of the answer. 
Result so far: 5755.04
Subtract 360 from 400 to get 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Going ahead to step 9:
400 divided by 90 is 4 with a remainder of 40.
Write down 4 as next digit of the result. 
Result so far: 5755.044
If we subtract 360 from 400, we get 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

The final result is 5755.044 with a remainder of 0.004.