CBEST cheat sheet

Main idea is the central claim of a passage; supporting details must explain, illustrate, or prove that claim.

A valid inference follows logically from textual evidence plus reasoning; it is not merely a plausible guess based on outside knowledge.

For vocabulary in context, substitute each answer choice into the original sentence and check whether meaning and tone remain coherent.

Author's purpose is the reason for writing, commonly to inform, persuade, entertain, or explain; purpose is inferred from content, structure, and language.

A fact can be verified with evidence; an opinion expresses a belief, judgment, or feeling and often uses evaluative words such as should, best, or beautiful.

Tone is the author's attitude toward the subject or audience; mood is the emotional atmosphere the text creates in the reader.

Compare-and-contrast questions require identifying the criteria being compared and whether the passage emphasizes similarity, difference, or both.

Evaluating an argument means separating claim from evidence and assumption; correlation alone does not establish causation.

Percent relationship: part = percent × whole; whole = part ÷ percent; percent = part ÷ whole × 100%.

Percent change = (new value − old value) ÷ old value × 100%; a positive result is an increase and a negative result is a decrease.

Fraction operations: add or subtract only after finding a common denominator; divide by multiplying by the reciprocal.

Proportion rule: if a/b = c/d, then ad = bc; scale factor multiplies every corresponding linear dimension.

Slope = (y₂ − y₁)/(x₂ − x₁); a linear equation can be written as y = mx + b, where m is slope and b is y-intercept.

Geometry formulas: rectangle A = lw and P = 2(l + w); triangle A = ½bh; circle C = 2πr and A = πr².

Mean = sum of values ÷ number of values; median = middle ordered value; mode = most frequent value; range = maximum − minimum.

Probability = favorable outcomes ÷ total equally likely outcomes; for independent events, multiply their individual probabilities.

Unit conversion uses a fraction equal to one so unwanted units cancel; order of operations is parentheses, exponents, multiplication/division, then addition/subtraction, left to right.

A thesis states the essay's main claim and often previews organization; a persuasive thesis must be arguable, not merely factual.

Paragraph unity requires one controlling idea, usually stated in a topic sentence, with all details serving that idea.

Transitions signal relationships: addition (also), contrast (however), cause (therefore), example (for instance), and sequence (first, next).

Subject-verb agreement: a singular subject takes a singular verb and a plural subject takes a plural verb; prepositional phrases between them do not change the subject.

Pronoun-antecedent agreement: a pronoun must match its antecedent in number and gender.

Comma rules: use a comma before a coordinating conjunction joining independent clauses, after introductory elements, and around nonessential clauses.

A semicolon joins closely related independent clauses; a colon follows a complete clause to introduce a list or explanation.

Place modifiers next to the words they describe; a dangling modifier lacks a clear subject in the main clause.

Essay scoring emphasizes a clear position, logical organization, specific support, and control of grammar, usage, and mechanics.