We look at the division of 538517 by 57 
The aim is to understand the frequency of 57 in 538517.

Advancing to step 1:
57 goes into 5 0 times with a remainder of 5.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 5 after subtracting 0 from 5.
Include the next digit (3) from the dividend after 5, then repeat: 53 / 57

On to step 2:
When dividing 53 by 57, we get 0 with a remainder of 53.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 53 leaves us with 53.
Fetch the next digit (8) from the dividend, attach it to 53 and continue: 538 / 57

Advancing to step 3:
57 can be fit into 538 9 times, resulting in a remainder of 25.
Use 9 as the next digit of our solution. 
Result so far: 9.0
Subtract 513 from 538 to get 25.
Grab the next digit (5) from the dividend, add it to 25, then carry on: 255 / 57

Step 4:
57 goes into 255 4 times with a remainder of 27.
Put 4 as the next digit of the answer. 
Result so far: 94.0
The remainder is 27 after subtracting 228 from 255.
Fetch the next digit (1) from the dividend, attach it to 27 and continue: 271 / 57

Step 5:
The number 57 fits into 271 4 times, leaving a remainder of 43.
Put 4 as the next digit of the answer. 
Result so far: 944.0
If we subtract 228 from 271, we get 43.
Append the next digit (7) from the dividend to 43 and continue with: 437 / 57

On to step 6:
437 divided by 57 is 7 with a remainder of 38.
The number 7 becomes the next digit in our result. 
Result so far: 9447.0
Subtract 399 from 437 to get 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

Advancing to step 7:
57 goes into 380 6 times with a remainder of 38.
Put 6 as the next digit of the answer. 
Result so far: 9447.6
If we take 342 away from 380, we end up with 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

Step 8:
380 divided by 57 is 6 with a remainder of 38.
Put 6 as the next digit of the answer. 
Result so far: 9447.66
The remainder is 38 after subtracting 342 from 380.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

After the division, we end up with 9447.66 and a remainder of 0.038.