You only have parenthesis (bracket), addition and subtraction here, so start with parenthesis: work out 3+5. This is 8, so remember the result.
You can do the whole problem by taking the numbers in the order they come: 500-25=475 plus the result we remembered (8)=483 minus 2=481.
Or we can take all the positives together first: 500+8=508, then all the negatives -25-2=-27 and subtract 27 from 508=481.