3 Most Common Mistakes in SAT/ACT Math

Most students wonder why they keep on making careless mistakes in math even after they have spent a lot of time practising the test questions.  The reason can be due to 3 common habits that are the real source of these mistakes.

The first mistake is that many students try to solve the problem with mental math.  They either underestimate the complexity of the problem or overestimate their mental math ability.  The truth is: mental math is the LEAST reliable way of performing calculations.  In my years as a math-major in college and a tutor in SAT/ACT, I have not met a single person who can perform mental math with reliable accuracy.  A lot of students (and parents) may regard mental math as the epitome of math skills, but in today’s world of sophisticated calculators and superfast computers, human minds simply cannot outmanoeuvre computers.  Neither should we try.  With the exception of the simplest questions, all calculations should be done ON PAPER.  That way, we can avoid careless mistakes and check our workings again if our answers do not match with the choices.

The next most common mistake is reading the question without knowing what it is asking for.  Often times, we assume that we know what the question is asking for, or we are so eager to dive into the problem that we did not even read carefully what it is asking for.  To correct this mistake, we have to read what the question and then CIRCLE it.  That way, we can always keep it in focus.  When we are ready to input the answer, whether into the answer sheet or computer, we should read the circled part again to make sure that we are answering the question.  Furthermore, all data given by the question should be UNDERLINED so that we always have a clear view of all the information given.

The third mistake is copying an expression or equation and then dive directly into the problem without checking what we have copied is correct.  Before we start working, take a few seconds to check that we have transcribed everything correctly.  Otherwise, we may find that we have wasted a lot of time working on the wrong problem.  In the process of setting up an expression or an equation to solve, we also need to check that it is correct before we start to work on the calculation.

Generally, good habits can be instilled and improved with practice.  But practice has to be done with deliberate purpose, and random practice will not lead to effective performance.  Otherwise, careless mistakes will continue to be elusive.

Mr. Paul Lim
Kaplan SAT and ACT Trainer
MBA, National University of Singapore
B.Sc., Harvey Mudd College
TBE | TESOL

• Over 15+ years of experience in teaching SAT and ACT
• Graduated from a prestigious U.S. college
• Proven record in helping students achieve a perfect subject section score of 800
• Author of a book on effective learning strategies for mastering vocabulary