We're dividing 670810 by 90 
The aim is to understand the frequency of 90 in 670810.

Step 1:
90 goes into 6 0 times with a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Include the next digit (7) from the dividend after 6, then repeat: 67 / 90

Advancing to step 2:
90 goes into 67 0 times with a remainder of 67.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 67 and we're left with 67.
Bring next digit (0) of the dividend behind the 67 and repeat the process: 670 / 90

Moving on to step 3:
The number 90 fits into 670 7 times, leaving a remainder of 40.
The number 7 becomes the next digit in our result. 
Result so far: 7.0
Subtract 630 from 670 to get 40.
Fetch the next digit (8) from the dividend, attach it to 40 and continue: 408 / 90

Advancing to step 4:
408 divided by 90 is 4 with a remainder of 48.
The next digit of our result is 4. 
Result so far: 74.0
Subtract 360 from 408 to get 48.
Fetch the next digit (1) from the dividend, attach it to 48 and continue: 481 / 90

Advancing to step 5:
90 can be fit into 481 5 times, resulting in a remainder of 31.
Use 5 as the next digit of our solution. 
Result so far: 745.0
If we subtract 450 from 481, we get 31.
Append the next digit (0) from the dividend to 31 and continue with: 310 / 90

Going ahead to step 6:
90 can be fit into 310 3 times, resulting in a remainder of 40.
Use 3 as the next digit of our solution. 
Result so far: 7453.0
The remainder is 40 after subtracting 270 from 310.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Moving on to step 7:
90 goes into 400 4 times with a remainder of 40.
Write down 4 as next digit of the result. 
Result so far: 7453.4
Subtract 360 from 400 to get 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Step 8:
The number 90 fits into 400 4 times, leaving a remainder of 40.
Put 4 as the next digit of the answer. 
Result so far: 7453.44
The remainder is 40 after subtracting 360 from 400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Our division results in 7453.44 with a remaining 0.04.