688011 ÷ 90 
The aim is to understand the frequency of 90 in 688011.

Going ahead to step 1:
90 goes into 6 0 times with a remainder of 6.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Bring next digit (8) of the dividend behind the 6 and repeat the process: 68 / 90

Step 2:
90 can be fit into 68 0 times, resulting in a remainder of 68.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 68, we get 68.
Include the next digit (8) from the dividend after 68, then repeat: 688 / 90

Let's proceed to step 3:
90 goes into 688 7 times with a remainder of 58.
The number 7 becomes the next digit in our result. 
Result so far: 7.0
If we subtract 630 from 688, we get 58.
Grab the next digit (0) from the dividend, add it to 58, then carry on: 580 / 90

On to step 4:
If we divide 580 by 90, we get 6 and a remainder of 40.
Use 6 as the next digit of our solution. 
Result so far: 76.0
Subtracting 540 from 580 leaves us with 40.
Include the next digit (1) from the dividend after 40, then repeat: 401 / 90

On to step 5:
90 goes into 401 4 times with a remainder of 41.
Put 4 as the next digit of the answer. 
Result so far: 764.0
Deduct 360 from 401 and we're left with 41.
Grab the next digit (1) from the dividend, add it to 41, then carry on: 411 / 90

On to step 6:
If we divide 411 by 90, we get 4 and a remainder of 51.
Use 4 as the next digit of our solution. 
Result so far: 7644.0
If we take 360 away from 411, we end up with 51.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

Going ahead to step 7:
90 can be fit into 510 5 times, resulting in a remainder of 60.
The number 5 becomes the next digit in our result. 
Result so far: 7644.5
Subtracting 450 from 510 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.

Let's proceed to step 8:
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: 7644.56
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.

Step 9:
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: 7644.566
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.

The final result is 7644.566 with a remainder of 0.006.