Problem Solving

Brian@VeritasPrep wrote:Great explanation, arora! One thing I want to chime in with - this is a fantastic example of just a pure "GMAT Problem". It's really easy for people to see a problem that only includes arithmetic (in this case addition) and see it as "easy" or even "too easy", and then start to think that their score is tanking because the question was too easy.

When you see questions that look easy, take a few seconds to try to find the difficulty. Ultimately, there are two main reasons that you could see an "easy" question on test day even if you are doing well:

1) It's an experimental question and they need to prove that someone scoring at your high level does, indeed, always get it right.

2) It's not an easy question, and you're just missing the difficulty.

#2 is a killer - the GMAT loves to sneak its difficulty past you without your ever knowing. So if a question looks "easy", look for the difficulty. What might you be missing? Often what you're missing is embedded in the definition of a term. Here, it's:

the greatest integer LESS THAN or EQUAL TO x.

The difficulty? "LESS THAN" gets us looking for a smaller absolute value. Mentally, we just assume that 1 is less than 2, negative sign be damned. But -1 is GREATER than -1.6. We need to, as arora mentioned, go left on the number line.

On a question like this, you should really be able to not just correctly round down to -2 + 3 + 2 = 3, but also be able to check off the "difficulty" and say "it's 3, but they want me to think 4 because of the negative". Much of success on this test comes from your ability to think like the testmaker - to know where the traps are coming from and which concepts the GMAT likes to use to set them. Even if this question was "easy" to you, look for where the difficulty lies and you'll get a better feel for how to take this test overall.