We look at the division of 684587 by 90 
The aim is to understand the frequency of 90 in 684587.

Step 1:
If we divide 6 by 90, we get 0 and a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Grab the next digit (8) from the dividend, add it to 6, then carry on: 68 / 90

Step 2:
68 divided by 90 is 0 with a remainder of 68.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 68, we end up with 68.
Bring next digit (4) of the dividend behind the 68 and repeat the process: 684 / 90

Moving on to step 3:
684 divided by 90 is 7 with a remainder of 54.
Use 7 as the next digit of our solution. 
Result so far: 7.0
The remainder is 54 after subtracting 630 from 684.
Bring next digit (5) of the dividend behind the 54 and repeat the process: 545 / 90

Step 4:
90 can be fit into 545 6 times, resulting in a remainder of 5.
Write down 6 as next digit of the result. 
Result so far: 76.0
Deduct 540 from 545 and we're left with 5.
Fetch the next digit (8) from the dividend, attach it to 5 and continue: 58 / 90

On to step 5:
If we divide 58 by 90, we get 0 and a remainder of 58.
Put 0 as the next digit of the answer. 
Result so far: 760.0
If we subtract 0 from 58, we get 58.
Grab the next digit (7) from the dividend, add it to 58, then carry on: 587 / 90

Going ahead to step 6:
If we divide 587 by 90, we get 6 and a remainder of 47.
The number 6 becomes the next digit in our result. 
Result so far: 7606.0
If we take 540 away from 587, we end up with 47.
Since there are no more digits in the dividend, we add a zero to the remainder making it 470, and continue the process.

Going ahead to step 7:
470 divided by 90 is 5 with a remainder of 20.
The next digit of our result is 5. 
Result so far: 7606.5
Deduct 450 from 470 and we're left with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Step 8:
If we divide 200 by 90, we get 2 and a remainder of 20.
Use 2 as the next digit of our solution. 
Result so far: 7606.52
Deduct 180 from 200 and we're left with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Going ahead to step 9:
200 divided by 90 is 2 with a remainder of 20.
Use 2 as the next digit of our solution. 
Result so far: 7606.522
If we take 180 away from 200, we end up with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

The quotient of the division is 7606.522, and the remainder is 0.002.