Test whether the conclusion follows.
For an argument, puzzle or set of conditions, write down the rule first. Then identify exactly what the proposed answer claims. Ask whether the information forces that claim, merely allows it, or contradicts it. This slows down an answer that only feels plausible.
- State the rule simply. Replace long wording with a short “if … then …” note where possible.
- State the claim. Say what an option is asserting.
- Test one case. Look for an example that breaks the claim, or for the chain that proves it.
- Choose only what the information supports. Do not add a rule that was not given.
Original worked example
Rule: Every student who borrows a chess set signs it out. Claim: “Linh signed out a chess set, so Linh played chess.” The rule says what follows from borrowing. It does not say that everyone who signs out a set borrows it, or that anyone who borrows it plays a game. Linh could have signed it out and then decided not to take it. Neither borrowing nor playing is proved by the rule alone.
Make a counterexample part of practice.
A counterexample is one possible situation in which a claim fails. It is especially useful when an option uses words such as “all”, “none”, “must” or “only”. The aim is not to distrust every statement; it is to check the link between evidence and conclusion.
Common error
Confusing “could be true” with “must be true”. Several answers may be possible in an imagined situation, while only one is required by the stated rules.
Self-check
Can the student name the exact rule that supports their choice, or provide a possible case that disproves it?