PSAT 8/9 common mistakes
PSAT 8/9 · Understand the traps and how to avoid them.
Answering a question about the main idea or purpose by picking the choice that is true according to one detail of the passage but does not cover the whole passage.
Under time pressure, students latch onto the first answer choice that mentions something they remember reading, so a vivid detail feels like the point of the passage even when it is only supporting evidence.
What to do instead
Before reading the choices, state the main idea in your own words in one sentence, then eliminate any choice that is narrower than that sentence, broader than it, or only about a single paragraph.
Choosing an answer to an evidence-based or command-of-evidence question without checking that the quoted lines actually support the claim, relying instead on the answer's overall plausibility.
Students evaluate the claim and the quotation separately rather than testing the link between them, and a quotation that is interesting or on the same topic feels supportive.
What to do instead
For each quotation choice, write a one-line bridge in the form 'this line shows X because...' If you cannot complete the bridge using the words of the line, the choice is wrong.
Treating transition and linking questions as a search for the word that sounds most formal, ignoring the logical relationship between the two sentences.
Students have been taught to prefer academic-sounding connectives, so 'nevertheless' or 'consequently' feels safer than a plain 'for example' even when the second sentence is an illustration.
What to do instead
Label the relationship first: same direction, contrast, cause-effect, example, or sequence. Then pick the choice whose meaning matches that label, and read the full sentence with the choice inserted to check it.
Reading the grammar passage sentence by sentence for meaning and never checking whether the underlined portion creates a fragment, run-on, or comma splice.
When a sentence sounds fine spoken aloud, students assume it is grammatically complete and skip the structural check that the question is actually testing.
What to do instead
For every sentence containing a blank or underlined portion, identify the subject and the main verb and count the independent clauses. If two independent clauses are joined only by a comma or nothing, the choice is wrong regardless of how it sounds.
Spending the same amount of time on every reading question, so early dense questions consume the clock and the final passage is answered in a rushed minute.
Students treat finishing every question with full deliberation as the goal, without tracking that later questions are worth exactly as much as earlier ones.
What to do instead
Set a per-question time budget during practice (roughly one minute for reading, less for grammar), and rehearse a rule: if a question is still unresolved at the budget, mark a best guess and move on.
Solving a linear equation or inequality by performing an operation on one side only, or forgetting to flip the inequality sign when multiplying or dividing by a negative.
The steps are done mentally and quickly, and the sign-flip rule is easy to state but easy to drop when attention is on arithmetic.
What to do instead
Write each operation on both sides explicitly, and circle any negative multiplier or divisor before applying it; when you circle one, rewrite the inequality with the flipped sign immediately.
Setting up a word problem with the variables assigned to the wrong quantities, for example writing the number of adult tickets as the number of child tickets.
Students translate the problem directly into symbols without first naming what each variable represents, so the equation is internally consistent but models the wrong situation.
What to do instead
Before writing any equation, write 'let x = ...' and 'let y = ...' in words, then check each term of the equation against those definitions and confirm the units match.
Answering the question that was asked with a value that is an intermediate result, such as giving x when the question asks for 3x + 2 or for the total cost.
The algebra ends when x is found, and the relief of solving creates a stopping point before the final requested quantity is computed.
What to do instead
Underline the actual question in the prompt before starting, and after solving, return to that underlined phrase and compute the requested quantity from your result.
Estimating a graph or table reading from the visual shape of the line instead of reading the labeled scale and the actual plotted values.
Axes with non-unit increments or truncated origins make a steep-looking line seem to have a larger slope or intercept than the numbers show.
What to do instead
Read the axis labels and tick spacing first, then identify two points whose coordinates you can read exactly from gridlines and compute slope from those coordinates rather than from appearance.
Leaving answers in an unrequested form, such as a fraction where a decimal is required or an unsimplified expression, and misreading what the answer box accepts.
Students focus on getting a numerical value and do not check the instructions about form, rounding, or whether the answer must be an integer.
What to do instead
Before submitting, reread the answer instructions and convert your result to the required form, checking rounding rules and whether a fraction, decimal, or expression is expected.