665897 ÷ 90 
The aim is to understand the frequency of 90 in 665897.

Advancing to step 1:
The number 90 fits into 6 0 times, leaving a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Fetch the next digit (6) from the dividend, attach it to 6 and continue: 66 / 90

Step 2:
The number 90 fits into 66 0 times, leaving a remainder of 66.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 66 leaves us with 66.
Include the next digit (5) from the dividend after 66, then repeat: 665 / 90

Advancing to step 3:
The number 90 fits into 665 7 times, leaving a remainder of 35.
Record the quotient 7 as the next digit in the result. 
Result so far: 7.0
If we subtract 630 from 665, we get 35.
Include the next digit (8) from the dividend after 35, then repeat: 358 / 90

Going ahead to step 4:
90 goes into 358 3 times with a remainder of 88.
The number 3 becomes the next digit in our result. 
Result so far: 73.0
If we take 270 away from 358, we end up with 88.
Fetch the next digit (9) from the dividend, attach it to 88 and continue: 889 / 90

Advancing to step 5:
90 goes into 889 9 times with a remainder of 79.
Use 9 as the next digit of our solution. 
Result so far: 739.0
Deduct 810 from 889 and we're left with 79.
Take the next digit (7) from the dividend and append it to 79, then repeat: 797 / 90

Going ahead to step 6:
90 can be fit into 797 8 times, resulting in a remainder of 77.
Use 8 as the next digit of our solution. 
Result so far: 7398.0
If we take 720 away from 797, we end up with 77.
Since there are no more digits in the dividend, we add a zero to the remainder making it 770, and continue the process.

Moving on to step 7:
90 can be fit into 770 8 times, resulting in a remainder of 50.
Record the quotient 8 as the next digit in the result. 
Result so far: 7398.8
If we take 720 away from 770, we end up 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.

Going ahead to step 8:
When dividing 500 by 90, we get 5 with a remainder of 50.
Use 5 as the next digit of our solution. 
Result so far: 7398.85
The remainder is 50 after subtracting 450 from 500.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Going ahead to step 9:
90 can be fit into 500 5 times, resulting in a remainder of 50.
Put 5 as the next digit of the answer. 
Result so far: 7398.855
Deduct 450 from 500 and we're left 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.

The quotient of the division is 7398.855, and the remainder is 0.005.