We look at the division of 510520 by 45 
The aim is to understand the frequency of 45 in 510520.

On to step 1:
45 goes into 5 0 times with a remainder of 5.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 5, we get 5.
Take the next digit (1) from the dividend and append it to 5, then repeat: 51 / 45

On to step 2:
45 can be fit into 51 1 times, resulting in a remainder of 6.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we subtract 45 from 51, we get 6.
Include the next digit (0) from the dividend after 6, then repeat: 60 / 45

On to step 3:
If we divide 60 by 45, we get 1 and a remainder of 15.
Use 1 as the next digit of our solution. 
Result so far: 11.0
If we subtract 45 from 60, we get 15.
Bring next digit (5) of the dividend behind the 15 and repeat the process: 155 / 45

Moving on to step 4:
45 goes into 155 3 times with a remainder of 20.
Write down 3 as next digit of the result. 
Result so far: 113.0
If we subtract 135 from 155, we get 20.
Bring next digit (2) of the dividend behind the 20 and repeat the process: 202 / 45

Advancing to step 5:
The number 45 fits into 202 4 times, leaving a remainder of 22.
Put 4 as the next digit of the answer. 
Result so far: 1134.0
Subtract 180 from 202 to get 22.
Bring next digit (0) of the dividend behind the 22 and repeat the process: 220 / 45

Step 6:
220 divided by 45 is 4 with a remainder of 40.
The number 4 becomes the next digit in our result. 
Result so far: 11344.0
Subtract 180 from 220 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.

Going ahead to step 7:
The number 45 fits into 400 8 times, leaving a remainder of 40.
Record the quotient 8 as the next digit in the result. 
Result so far: 11344.8
If we subtract 360 from 400, we 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.

Moving on to step 8:
45 goes into 400 8 times with a remainder of 40.
The number 8 becomes the next digit in our result. 
Result so far: 11344.88
If we subtract 360 from 400, we 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.

Our division results in 11344.88 with a remaining 0.04.