When encounter questions that ask for operation on algebraic expressions, using BODMAS or PEMDAS method would be easier. Since this question asked for using BODMAS, then it is:
To figure out you would first find a common factor with would be 12. After that 1/4 would be 3/12, 1/3 would be 4/12 and 1/6 would be 2/12. Next you just add all the numbers and get 9/12 then the remainder is you answer which comes to be 3/12 or 1/4. Hope that helps:)