Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 49206

Biggest GMAT Mistakes You Should Avoid
[#permalink]
Show Tags
Updated on: 23 Jan 2014, 04:03
CARELESS MISTAKESCareless errors are the #1 cause of score drops on the GMAT! They cause you to miss easier questions, hurting your score a lot more than not know how to solve the harder ones. The biggest mistake that GMAT students make when studying is not tracking errors from the very beginning. If you want to improve your score on the GMAT, it’s not enough just to know which problems you got wrong. You need to know why you got them wrong. 1. Answering the wrong question/solved for the wrong variable
If a question asks, “how many gallons are left in the bucket after 40 percent is removed?” or “If x + y = 7 and x – y = 1, what is the value of y?”, your math will almost always lead you to solve first for the number of gallons removed or the value of x. You will end up with a number on your noteboard that matches an answer choice—but that represents the right answer to the wrong question. When there are two variables or entities in a problem, or when multiple intermediate steps are required to solve it, there’s nearly always an incorrect answer choice that matches the other variable or the number you get one step before the problem is finished. Before you submit your answer, doublecheck that it’s the answer to the proper question.
2. Forgetting to consider “unique” numbers
Particularly in Data Sufficiency questions, standard counting numbers such as 2, 3, 4, etc., will react one way, but the lessobvious numbers such as fractions, negatives, and zero may behave another. Often in your haste to answer the question quickly, you forget to consider a type of number that would change the answer completely. For example, if a question asks “Is x > 3?” and you’re given the information that x^2 = 25, you might quickly think “x = 5, so yes.” But what about 5? That’s a less obvious number to consider—your mind isn’t that calibrated to think about negatives—but it changes the answer, as just given that x^2 = 25, we don’t know whether x is greater than 3.
And while that’s a relatively basic example, remember this: The GMAT is incredibly adept at getting you to make this exact mistake (forgetting to consider negatives) on tricky questions. Questions that involve a clever math step or two often get you to let down your guard, so even the highestscoring students need to be aware of these traps.
3. Thinking that “no” means “not sufficient”
Also in Data Sufficiency questions, you’re asked to determine when you have enough information (when the data are sufficient) to answer a question. But since your standardizedtest mind is calibrated for the process of elimination, when those data are sufficient to give the direct answer “no,” you’re prone to cross wires and eliminate that answer. For example, if a question asks, “Is x a prime number?” and you’re given a statement “x = 17! + 51,” you should see that you have sufficient information to answer the question “no,” since both terms being added are multiples of 17, then x will be a multiple of 17 and therefore not prime. But your mind might say “no, it’s not prime … so NO on that statement,” when really you do have sufficient information.
Your job is to determine whether the information is sufficient, not whether the answer is “yes.”
4. Doing tedious calculations You Don't Need Long Division. The GMAT reliably uses a set of simple numbers. When it doesn't, you can usually approximate. There are few better uses of your study time for the math section than learning some mental math tricks. They will save you time on the exam, and you'll get a better grasp of how numbers "work together" for questions on topics such as factors and multiples.
5. Reading too quickly / misreading the question
6. Making an arithmetic error (got the wrong sum, product, etc)
7. Performed the wrong operation (multiplied instead of divided)
8. Misreading your own handwriting
9. Skipping a step
10. Clicking the wrong bubble STRATEGIC MISTAKES1. Do not even attempt to calculate a value for data sufficiency questions the moment you realize whether you would (or would not) be able to complete them.
Data sufficiency questions take some getting used to. You are asked not to calculate a value but to determine whether you are able to do so with the information supplied. So abandon your computations the moment you realize whether you would (or would not) be able to complete them. On Data Sufficiency questions, there's no place to enter a numerical answer. Still, too many students don't feel confident in saying that a statement is sufficient until they've solved for x. It's a waste of time.
2. Do not shy away from C or E in data sufficiency problems because of the way they look.
Students display certain predictable behavioral weaknesses that the GMAT exploits. In data sufficiency, test takers may be reluctant to choose answer “C,” which typically states that both statements together are sufficient, but neither statement alone is—it seems too easy. Similarly answer “E,” stating that the question cannot be answered, feels like failure (it’s not), so candidates shy away from it. Be aware of these subconscious influences.
3. Do not overcalculate.
On quantitative questions that require a numerical answer, don’t waste time on elaborate computations. If your scratch paper is covered with numbers, you’re doing it wrong. Your ability to emulate a calculator is not what GMAT is interested in. So, do not get bogged down with complicated or lengthy calculations.
4. Determine the amount of calculation needed based on the answer choices.
If the question contains the word “approximately” or the answer choices are widely spread in value, GMAT is telling you that you should save some time by making approximations. Conversely, if the values of the answer choices are close together, this is sign that GMAT expects you to compute the answer precisely.
5. Stay away from the longhand approach. Take shortcuts: Plug in the answers and or eliminate them.
When it comes to problem solving, because the GMAT supplies five possible answer choices to each question, the task is not to calculate or derive an answer, but to choose one, a subtly different task. So in addition to the traditional analytical approach, there may be times when it’s quicker and more effective to adopt the numerical approach (also known as substitution, or “plugging in the answers”) or the logical approach (“which answers can I eliminate without calculation?”).
6. For DS questions do not assume anything on your own. Use only the information given in the questions.
7. In DS, both the statements may tell the same information but in different way.
When the 2 statements convey the same exact information, the correct answer choice will be either D or E.
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics
Originally posted by Bunuel on 20 Jan 2014, 07:19.
Last edited by Bunuel on 23 Jan 2014, 04:03, edited 3 times in total.
Work in progress.



Math Expert
Joined: 02 Sep 2009
Posts: 49206

Re: Biggest Mistakes You Should Avoid
[#permalink]
Show Tags
20 Jan 2014, 07:20



VP
Joined: 02 Jul 2012
Posts: 1191
Location: India
Concentration: Strategy
GPA: 3.8
WE: Engineering (Energy and Utilities)

Re: Biggest GMAT Mistakes You Should Avoid
[#permalink]
Show Tags
24 Jan 2014, 02:27
This needs to be added to the navigation menu bar... Great work as usual!!
_________________
Did you find this post helpful?... Please let me know through the Kudos button.
Thanks To The Almighty  My GMAT Debrief
GMAT Reading Comprehension: 7 Most Common Passage Types



Retired Moderator
Joined: 10 May 2010
Posts: 813

Re: Biggest GMAT Mistakes You Should Avoid
[#permalink]
Show Tags
27 Jan 2014, 11:44
In some cases maybe we can can add as to how can we avoid these mistakes.
_________________
The question is not can you rise up to iconic! The real question is will you ?



Current Student
Joined: 28 Feb 2013
Posts: 15
Location: United States
Concentration: Statistics, Strategy
GMAT Date: 03122014
WE: Information Technology (Other)

Re: Biggest GMAT Mistakes You Should Avoid
[#permalink]
Show Tags
12 Mar 2014, 12:51
Bunuel wrote: CARELESS MISTAKES
3. Thinking that “no” means “not sufficient”
Also in Data Sufficiency questions, you’re asked to determine when you have enough information (when the data are sufficient) to answer a question. But since your standardizedtest mind is calibrated for the process of elimination, when those data are sufficient to give the direct answer “no,” you’re prone to cross wires and eliminate that answer. For example, if a question asks, “Is x a prime number?” and you’re given a statement “x = 17! + 51,” you should see that you have sufficient information to answer the question “no,” since both terms being added are multiples of 17, then x will be a multiple of 17 and therefore not prime. But your mind might say “no, it’s not prime … so NO on that statement,” when really you do have sufficient information.
Your job is to determine whether the information is sufficient, not whether the answer is “yes.”
7. In DS, both the statements may tell the same information but in different way.
When the 2 statements convey the same exact information, the correct answer choice will be either D or E.[/list] These two issues are the source of my DS problems... I usually feel like im constrained by time so i make quick decisions because in reality DS questions are 3 questions in one: What is the stem really asking for? XY>0, or X>Y? And from there the two additional sufficiency questions. Because there are 15 DS questions out of 37, which can include any combination of combinatorics, exponents, percents, rates, geometry, or number theory, it multiplies the difficulty considerably. IMHO solving DS questions effectively is the core of doing well on GMAT. If you can do well on DS, everything else is cake.



NonHuman User
Joined: 09 Sep 2013
Posts: 8065

Re: Biggest GMAT Mistakes You Should Avoid
[#permalink]
Show Tags
02 Jul 2018, 06:15
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources




Re: Biggest GMAT Mistakes You Should Avoid &nbs
[#permalink]
02 Jul 2018, 06:15






