ATF Special Agent cheat sheet

Analogy bridges to check in order: synonym/antonym, part-to-whole, category-to-member, cause-to-effect, function (tool-to-user), degree (warm-to-scorching), and worker-to-tool.

Contrast signals (although, despite, whereas, nonetheless, paradoxically) reverse sentence direction so the blank opposes the stated idea; continuation signals (because, thus, moreover, since) keep direction the same.

Antonym items require the choice opposite in the same part of speech, tone, and specific word sense; an opposite of a different dictionary sense is a trap.

Reading comprehension main-idea answers must cover every paragraph; choices that only restate one detail or one example are wrong regardless of accuracy.

Scope rule: eliminate any choice making a stronger or broader claim than the passage supports, especially choices containing all, never, always, only, or must.

Vocabulary in context is tested by substituting each option back into the original sentence and checking whether the sentence's logic and tone survive.

On two-blank sentence items, use the easier blank to eliminate choices first, then confirm the survivor fits both the second blank and the overall logic.

Common combining forms: bene- (good), mal- (bad), cred- (believe), loqu- (speak), pug- (fight), ten- (hold), ver- (truth), and -cide (killing).

Percent change = (new value − old value) ÷ old value × 100; the denominator is always the original amount, not the new one.

Successive percent changes multiply as decimal factors: a 20% rise then a 10% fall gives 1.2 × 0.9 = 1.08, a net gain of 8%.

Average = sum ÷ count, so sum = average × count; this identity recovers a missing total or an unknown data point.

Combined work rate adds rates, not times: with individual times a and b, time together = ab ÷ (a + b).

For equal distances traveled at speeds a and b, average speed is the harmonic mean 2ab ÷ (a + b), not (a + b) ÷ 2.

Mixture and interest: solute = concentration × volume (add solutes, add volumes); simple interest I = Prt; compound A = P(1 + r/n)^(nt).

Special triangles: 45-45-90 sides are in ratio 1:1:√2; 30-60-90 sides are in ratio 1:√3:2 opposite those angles; 3-4-5 and 5-12-13 are common integer triples.

Divisibility tests: 3 by digit sum, 4 by last two digits, 8 by last three digits, 9 by digit sum, 6 by divisibility by both 2 and 3.

Independent events: multiply probabilities; mutually exclusive events: add probabilities; the complement rule gives P(not A) = 1 − P(A).

From 'if P then Q' only the contrapositive 'if not Q then not P' follows; the converse (Q → P) and the inverse (not P → not Q) are invalid.

'P only if Q' translates to P → Q, so Q is necessary; 'P if Q' translates to Q → P, so Q is sufficient.

'P unless Q' translates to 'if not Q then P'; unless introduces the condition whose absence triggers the result.

Sufficient condition guarantees the conclusion; necessary condition is required for it but may not guarantee it - confusing the two is the most common flaw tested.

Negation test for assumptions: negate a candidate statement; if the negation destroys the argument, that statement is a required assumption.

Syllogism chains: All A are B plus All B are C yields All A are C; a chain containing a 'some' premise yields only a 'some' conclusion, never an 'all'.

Strengthen or weaken by attacking the evidence-to-conclusion link: alternate cause, unrepresentative sample, reversed causation, or a term shift between premises and conclusion.

Named flaws: ad hominem, circular reasoning, post hoc (sequence treated as cause), hasty generalization, false dilemma, straw man, and appeal to authority.

Ordering games: draw a numbered line, record fixed placements and blocks (A immediately before B), and test the most restrictive rule first.

Subject-verb agreement: ignore prepositional phrases between subject and verb; each, every, either, and neither are singular; subjects joined by 'and' are plural; with or/nor the verb agrees with the nearer subject.

An introductory descriptive phrase must modify the subject of the main clause; otherwise it dangles (wrong: 'Walking to the car, the rain began').

Who is a subject pronoun, whom an object pronoun; after a preposition or as a direct object, use whom ('between you and me').

Two independent clauses cannot be joined by a comma alone (comma splice); use a period, a semicolon, or a comma plus a coordinating conjunction (and, but, or, nor, for, so, yet).

A semicolon joins two independent clauses with no conjunction following it; a colon follows a complete clause and introduces a list or explanation.

Parallelism: items in a list, comparison, or compound must share grammatical form - noun with noun, gerund with gerund, infinitive with infinitive.

Fewer with countable items (fewer agents), less with uncountable amounts (less time); between for two, among for three or more.

Its is possessive; it's means 'it is' or 'it has'. Apostrophe placement: singular possessive adds 's, plural possessive adds only the apostrophe after the final s.