First thing I can think of to avoid this problem is to solve tens of similar type of practice problems, check your answers and review them against a solution manual (hopefully a detailed one that walks you through the solution and common mistakes) or with an experienced tutor.
One other approach that seems to help in multiple choice tests is to streamline the solution process with necessary checks to make sure you avoid all trap doors. Take a look at the following Solution Flow TM. It will help you avoid at least one simple mistake per test.
1. Read the question carefully underlining words such as; less than, no greater than, must be true, greatest possible value, etc.
2. Glance at the answer choices before starting your solution. Make a note of the format of the answer choices. Are they numbers or variables? Are they fractions, decimals or integers? Are they in exponent or radical form? This alone could save you some valuable time by putting your answer in the correct format without having to adjust later.
3. Solve the problem (more on that later)
4. Very important step: Go back to the question and say “what is the question asking me?” and read the last statement that contains the question.
5. Answer the correct question!
A large number of so called “stupid mistakes” result from assuming what the question is and answering the wrong one. Especially in SAT, these type of wrong answers are almost always among the answer choices.
Here’s a very simple example:
If 3x + y = 8 and -8x – y = 7, what is the value of x+y?
A. -3
B. 3
C. 14
D. 15
E. 17
You can use elimination for this problem:
3x + y = 8
-8x – y = 7
-5x=15 à x=-3 … y=17 don’t mark -3 or 17.
Go back to the last sentence in the question:…what is the value of x+y?
So; -3+17=14 the answer is C
As you can see, this method is not specific to any particular test and could effectively be applied to any multiple choice math question.
