We're dividing 546409 by 90 
The aim is to understand the frequency of 90 in 546409.

Step 1:
When dividing 5 by 90, we get 0 with a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 5 leaves us with 5.
Bring next digit (4) of the dividend behind the 5 and repeat the process: 54 / 90

Let's proceed to step 2:
90 goes into 54 0 times with a remainder of 54.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 54 to get 54.
Fetch the next digit (6) from the dividend, attach it to 54 and continue: 546 / 90

Step 3:
90 goes into 546 6 times with a remainder of 6.
Use 6 as the next digit of our solution. 
Result so far: 6.0
The remainder is 6 after subtracting 540 from 546.
Include the next digit (4) from the dividend after 6, then repeat: 64 / 90

Let's proceed to step 4:
If we divide 64 by 90, we get 0 and a remainder of 64.
Use 0 as the next digit of our solution. 
Result so far: 60.0
Subtracting 0 from 64 leaves us with 64.
Take the next digit (0) from the dividend and append it to 64, then repeat: 640 / 90

Step 5:
The number 90 fits into 640 7 times, leaving a remainder of 10.
Record the quotient 7 as the next digit in the result. 
Result so far: 607.0
Subtracting 630 from 640 leaves us with 10.
Grab the next digit (9) from the dividend, add it to 10, then carry on: 109 / 90

Going ahead to step 6:
90 can be fit into 109 1 times, resulting in a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 6071.0
If we subtract 90 from 109, we get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Going ahead to step 7:
The number 90 fits into 190 2 times, leaving a remainder of 10.
Use 2 as the next digit of our solution. 
Result so far: 6071.2
If we take 180 away from 190, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Moving on to step 8:
90 goes into 100 1 times with a remainder of 10.
Write down 1 as next digit of the result. 
Result so far: 6071.21
Deduct 90 from 100 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

On to step 9:
If we divide 100 by 90, we get 1 and a remainder of 10.
The next digit of our result is 1. 
Result so far: 6071.211
If we take 90 away from 100, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

After the division, we end up with 6071.211 and a remainder of 0.001.