731642 ÷ 90 
The aim is to understand the frequency of 90 in 731642.

Step 1:
When dividing 7 by 90, we get 0 with a remainder of 7.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 7, we get 7.
Fetch the next digit (3) from the dividend, attach it to 7 and continue: 73 / 90

Step 2:
When dividing 73 by 90, we get 0 with a remainder of 73.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 73 and we're left with 73.
Fetch the next digit (1) from the dividend, attach it to 73 and continue: 731 / 90

Advancing to step 3:
731 divided by 90 is 8 with a remainder of 11.
The number 8 becomes the next digit in our result. 
Result so far: 8.0
Subtracting 720 from 731 leaves us with 11.
Include the next digit (6) from the dividend after 11, then repeat: 116 / 90

Going ahead to step 4:
90 can be fit into 116 1 times, resulting in a remainder of 26.
The next digit of our result is 1. 
Result so far: 81.0
If we take 90 away from 116, we end up with 26.
Fetch the next digit (4) from the dividend, attach it to 26 and continue: 264 / 90

Moving on to step 5:
90 can be fit into 264 2 times, resulting in a remainder of 84.
The next digit of our result is 2. 
Result so far: 812.0
The remainder is 84 after subtracting 180 from 264.
Take the next digit (2) from the dividend and append it to 84, then repeat: 842 / 90

Step 6:
When dividing 842 by 90, we get 9 with a remainder of 32.
The number 9 becomes the next digit in our result. 
Result so far: 8129.0
Deduct 810 from 842 and we're left with 32.
Since there are no more digits in the dividend, we add a zero to the remainder making it 320, and continue the process.

Advancing to step 7:
When dividing 320 by 90, we get 3 with a remainder of 50.
The next digit of our result is 3. 
Result so far: 8129.3
If we take 270 away from 320, 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:
90 can be fit into 500 5 times, resulting in a remainder of 50.
Use 5 as the next digit of our solution. 
Result so far: 8129.35
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.

Going ahead to step 9:
The number 90 fits into 500 5 times, leaving a remainder of 50.
The next digit of our result is 5. 
Result so far: 8129.355
If we take 450 away from 500, 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.

The final outcome is 8129.355, with a leftover of 0.005.