We look at the division of 505060 by 45 
The aim is to understand the frequency of 45 in 505060.

On to step 1:
The number 45 fits into 5 0 times, leaving a remainder of 5.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 5, we end up with 5.
Include the next digit (0) from the dividend after 5, then repeat: 50 / 45

Step 2:
45 goes into 50 1 times with a remainder of 5.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we subtract 45 from 50, we get 5.
Include the next digit (5) from the dividend after 5, then repeat: 55 / 45

On to step 3:
When dividing 55 by 45, we get 1 with a remainder of 10.
Write down 1 as next digit of the result. 
Result so far: 11.0
Deduct 45 from 55 and we're left with 10.
Bring next digit (0) of the dividend behind the 10 and repeat the process: 100 / 45

Let's proceed to step 4:
If we divide 100 by 45, we get 2 and a remainder of 10.
Record the quotient 2 as the next digit in the result. 
Result so far: 112.0
If we subtract 90 from 100, we get 10.
Append the next digit (6) from the dividend to 10 and continue with: 106 / 45

Going ahead to step 5:
45 can be fit into 106 2 times, resulting in a remainder of 16.
The next digit of our result is 2. 
Result so far: 1122.0
Subtracting 90 from 106 leaves us with 16.
Bring next digit (0) of the dividend behind the 16 and repeat the process: 160 / 45

Advancing to step 6:
160 divided by 45 is 3 with a remainder of 25.
The number 3 becomes the next digit in our result. 
Result so far: 11223.0
If we take 135 away from 160, we end up with 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

Advancing to step 7:
45 can be fit into 250 5 times, resulting in a remainder of 25.
The number 5 becomes the next digit in our result. 
Result so far: 11223.5
Subtracting 225 from 250 leaves us with 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

Advancing to step 8:
If we divide 250 by 45, we get 5 and a remainder of 25.
The next digit of our result is 5. 
Result so far: 11223.55
If we subtract 225 from 250, we get 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

After the division, we end up with 11223.55 and a remainder of 0.025.