Let's divide 856400 by 90
The aim is to understand the frequency of 90 in 856400.

Step 1:
The number 90 fits into 8 0 times, leaving a remainder of 8.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Bring next digit (5) of the dividend behind the 8 and repeat the process: 85 / 90

On to step 2:
If we divide 85 by 90, we get 0 and a remainder of 85.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 85 and we're left with 85.
Grab the next digit (6) from the dividend, add it to 85, then carry on: 856 / 90

Going ahead to step 3:
90 goes into 856 9 times with a remainder of 46.
Record the quotient 9 as the next digit in the result. 
Result so far: 9.0
Subtracting 810 from 856 leaves us with 46.
Fetch the next digit (4) from the dividend, attach it to 46 and continue: 464 / 90

Going ahead to step 4:
90 can be fit into 464 5 times, resulting in a remainder of 14.
Record the quotient 5 as the next digit in the result. 
Result so far: 95.0
The remainder is 14 after subtracting 450 from 464.
Take the next digit (0) from the dividend and append it to 14, then repeat: 140 / 90

Advancing to step 5:
If we divide 140 by 90, we get 1 and a remainder of 50.
The next digit of our result is 1. 
Result so far: 951.0
If we subtract 90 from 140, we get 50.
Fetch the next digit (0) from the dividend, attach it to 50 and continue: 500 / 90

Step 6:
The number 90 fits into 500 5 times, leaving a remainder of 50.
The next digit of our result is 5. 
Result so far: 9515.0
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.

Moving on to step 7:
If we divide 500 by 90, we get 5 and a remainder of 50.
The next digit of our result is 5. 
Result so far: 9515.5
Subtract 450 from 500 to get 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Advancing to step 8:
If we divide 500 by 90, we get 5 and a remainder of 50.
Record the quotient 5 as the next digit in the result. 
Result so far: 9515.55
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 9515.55, and the remainder is 0.05.