Sometimes we have to do the math setup up front. Other times it helps to briefly glance at the information given, because that will actually inform what we are looking for and how we should set up the problem.
For example in one of the rates unit conversion DS problems from the exam, if we do the setup first we actually have to convert twice, once for each statement. However if we glance at the statements we see that the units in the question are different from the units in the 2 statements. So if we convert first and then do the setup, we end up HALVING the amount of work.
Similarly, in RC it helps to do a 10 second skim just so we know where the passage is headed, and then do the depth reading+passage notes.
In all GMAT problems, even CR and SC, GMAC can reveal a crucial clue at any step of the way. Usually we should set up math as we read, but there are exceptions. GMAT is also testing for flexibility and adaptability, fluid intelligence.
For example in one of the rates unit conversion DS problems from the exam, if we do the setup first we actually have to convert twice, once for each statement. However if we glance at the statements we see that the units in the question are different from the units in the 2 statements. So if we convert first and then do the setup, we end up HALVING the amount of work.
Similarly, in RC it helps to do a 10 second skim just so we know where the passage is headed, and then do the depth reading+passage notes.
In all GMAT problems, even CR and SC, GMAC can reveal a crucial clue at any step of the way. Usually we should set up math as we read, but there are exceptions. GMAT is also testing for flexibility and adaptability, fluid intelligence.