866070 divided by 90 
The aim is to understand the frequency of 90 in 866070.

On to step 1:
8 divided by 90 is 0 with a remainder of 8.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 8 to get 8.
Bring next digit (6) of the dividend behind the 8 and repeat the process: 86 / 90

Going ahead to step 2:
The number 90 fits into 86 0 times, leaving a remainder of 86.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 86, we end up with 86.
Take the next digit (6) from the dividend and append it to 86, then repeat: 866 / 90

On to step 3:
When dividing 866 by 90, we get 9 with a remainder of 56.
The next digit of our result is 9. 
Result so far: 9.0
If we subtract 810 from 866, we get 56.
Fetch the next digit (0) from the dividend, attach it to 56 and continue: 560 / 90

Advancing to step 4:
90 can be fit into 560 6 times, resulting in a remainder of 20.
Write down 6 as next digit of the result. 
Result so far: 96.0
Subtract 540 from 560 to get 20.
Fetch the next digit (7) from the dividend, attach it to 20 and continue: 207 / 90

Going ahead to step 5:
90 goes into 207 2 times with a remainder of 27.
The next digit of our result is 2. 
Result so far: 962.0
The remainder is 27 after subtracting 180 from 207.
Grab the next digit (0) from the dividend, add it to 27, then carry on: 270 / 90

Step 6:
90 can be fit into 270 3 times, resulting in a remainder of 0.
The number 3 becomes the next digit in our result. 
Result so far: 9623.0
Subtracting 270 from 270 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 7:
90 goes into 0 0 times with a remainder of 0.
The next digit of our result is 0. 
Result so far: 9623.0
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 8:
If we divide 0 by 90, we get 0 and a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 9623.0
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The quotient of the division is 9623.0, and the remainder is 0.0.