ACT Question Types
Every question type across all four ACT sections — grammar rules with examples, math topic formulas, reading strategies, and science data skills.
English Section
75 questions · 45 minutes · 5 passages
Tests grammar, usage, rhetoric, and organization within the context of full prose passages.
Punctuation
Conventions of Standard English — 51-56%Tests your knowledge of commas, apostrophes, colons, semicolons, dashes, and periods. Questions ask you to choose correct punctuation within and between sentences.
Example Question
The research team, which included scientists from three countries[BLANK] published its findings last spring.
Strategy Tip
If a clause between commas can be removed without breaking the sentence, it needs commas on both sides. A semicolon connects two independent clauses; a comma alone cannot.
Grammar & Usage
Conventions of Standard English — 51-56%Covers subject-verb agreement, pronoun-antecedent agreement, verb tense consistency, pronoun case, and comparative/superlative forms.
Example Question
Each of the students in the advanced biology classes [has/have] completed the required lab hours.
Strategy Tip
Strip away prepositional phrases to find the true subject. 'Each' is singular, so it takes a singular verb regardless of what follows 'of.'
Sentence Structure
Conventions of Standard English — 51-56%Tests your ability to recognize and fix run-on sentences, comma splices, fragments, misplaced modifiers, and faulty parallelism.
Example Question
Running through the park at dawn, the sunrise painted the sky in shades of pink and gold. [Is this sentence correct?]
Strategy Tip
A participial phrase at the start of a sentence must modify the subject that follows. Here, 'running through the park' dangles because 'the sunrise' is not doing the running.
Topic Development
Production of Writing — 29-32%Asks whether to add, revise, or delete a sentence. Tests whether a detail supports the paragraph's main idea or is irrelevant.
Example Question
The writer is considering adding the following sentence. Should the writer make this addition? [Yes/No, because...]
Strategy Tip
Always identify the paragraph's main point first. If the proposed sentence supports it with relevant detail, keep it. If it introduces an unrelated tangent, delete it.
Organization, Unity & Cohesion
Production of Writing — 29-32%Tests logical ordering of sentences within a paragraph, placement of new sentences, and effective transitions between ideas.
Example Question
For the sake of the logic and coherence of this paragraph, Sentence 5 should be placed: [before Sentence 1 / after Sentence 2 / where it is now]
Strategy Tip
Look for chronological clues, pronoun references, and transition words. A sentence should logically follow from what comes before it and lead into what comes after.
Word Choice, Style & Tone
Knowledge of Language — 13-19%Tests choosing the most precise or appropriate word for context, eliminating wordiness, and maintaining a consistent tone throughout a passage.
Example Question
Which choice maintains the essay's formal, academic tone? A) got rid of B) eliminated C) threw out D) ditched
Strategy Tip
Match the word to the passage's tone. Academic passages need formal diction. When two choices are both grammatically correct, pick the one that is more concise and precise.
Punctuation Deep-Dive: The 8 Comma Rules
Comma questions appear on nearly every ACT English section. Master these 8 rules and you will handle most punctuation questions correctly.
Rule 1: Introductory Element
Use a comma after an introductory word, phrase, or clause that comes before the main clause.
Rule 2: Nonrestrictive Clause
Use commas around a nonrestrictive (non-essential) clause — one that can be removed without changing the sentence's core meaning. Do NOT use commas around a restrictive clause.
Rule 3: Coordinate Adjectives
Use a comma between two or more coordinate adjectives that independently modify the same noun. Test: if 'and' sounds natural between them, they are coordinate.
Rule 4: Compound Sentence (FANBOYS)
Use a comma before a coordinating conjunction (for, and, nor, but, or, yet, so) that joins two independent clauses.
Rule 5: Items in a Series
Use commas to separate three or more items in a series. The ACT uses the Oxford comma (before 'and' in a list of three or more).
Rule 6: Parenthetical Expressions
Use commas to set off parenthetical expressions (words/phrases that interrupt the main clause). Remove the expression — if the sentence still makes sense, use commas.
Rule 7: Direct Address
Use a comma to separate a name used in direct address (a person being spoken to directly) from the rest of the sentence.
Rule 8: No Comma Between Subject and Verb
Do NOT place a comma between a subject and its verb, or between a verb and its object. This is one of the most common incorrect comma placements on the ACT.
Apostrophe Rules
Apostrophe errors are among the most commonly tested grammar mistakes on the ACT. The its/it's confusion appears on nearly every test.
Possessive Singular
Add 's to make a singular noun possessive, even if it ends in s.
Possessive Plural (ends in -s)
For plural nouns that already end in -s, add only an apostrophe after the s to show possession.
Contractions vs. Possessives
Contractions use apostrophes (it's = it is; they're = they are; you're = you are). Possessive pronouns NEVER use apostrophes (its, their, your).
Plural Nouns (no apostrophe)
Do NOT use an apostrophe to form a simple plural. Apostrophes show possession or contraction, never plurality.
Semicolons & Colons
These two punctuation marks are frequently confused on the ACT. The key test: can both sides stand alone as complete sentences?
Semicolon: Join Two Independent Clauses
A semicolon joins two complete sentences (independent clauses) that are closely related. Both sides of a semicolon must be able to stand alone as complete sentences.
Semicolon Before Conjunctive Adverbs
When conjunctive adverbs (however, therefore, moreover, consequently, furthermore, nevertheless) connect two independent clauses, use a semicolon before and a comma after.
Colon: Introduction
A colon introduces a list, explanation, or quotation. The clause before the colon must be a complete sentence (independent clause).
Colon vs. Semicolon
Use a colon when what follows explains or elaborates on what precedes it. Use a semicolon when two clauses are equally weighted and closely related.
Grammar & Usage: Common Test Targets
| Error Type | The Trap | The Fix |
|---|---|---|
| Subject-Verb Agreement | Collective noun (team, committee) — singular or plural? | In American English, collective nouns take singular verbs: 'The team was…' |
| Pronoun-Antecedent Agreement | Singular indefinite pronouns (each, everyone, nobody) | 'Everyone should bring their…' is informal. ACT prefers 'his or her.' |
| Verb Tense Consistency | Mixing past and present tense within a passage | Keep the dominant tense consistent; shift only when indicating a genuine time change. |
| Pronoun Case | Who vs. whom; I vs. me | Use 'who/I' as subjects; 'whom/me' as objects. 'Give it to me,' not 'to I.' |
| Dangling Modifier | Introductory phrase that doesn't match the subject | Make the noun after the comma the doer of the introductory action. |
| Faulty Parallelism | List items in different grammatical forms | Keep all list items in the same form: 'running, jumping, and swimming' (all gerunds). |
| Comparative vs. Superlative | Using 'most' with '-est' or 'more' with '-er' | Never: 'most tallest.' Say either 'tallest' or 'most tall' (latter is unusual). |
| Double Negative | Using 'not' with 'hardly,' 'barely,' 'scarcely' | 'I can barely see' — not 'I can't barely see.' |
Math Section
60 questions · 60 minutes · Calculator allowed for all questions
Covers pre-algebra through early college math. Roughly in order of difficulty from easiest (Q1) to hardest (Q60).
All 15 Math Topic Areas
Integers & Number Properties
Pre-Algebra- Factors, multiples, LCM, GCF
- Prime numbers and prime factorization
- Order of operations (PEMDAS)
- Absolute value
Fractions, Decimals & Percentages
Pre-Algebra- Convert between fractions, decimals, and percentages
- Percent change = (new − old) / old × 100
- Percent of a number: multiply by decimal equivalent
Ratios, Proportions & Unit Rates
Pre-Algebra- Cross-multiply to solve proportions
- Rate problems: distance = rate × time
- Unit conversion using dimensional analysis
Linear Equations & Inequalities
Algebra- Solve by isolating the variable
- Flip the inequality sign when multiplying/dividing by a negative
- Graph linear inequalities: solid line (≤/≥), dashed line (</>)
Systems of Equations
Algebra- Substitution method: solve one equation, substitute
- Elimination method: add/subtract equations to cancel a variable
- Number of solutions: intersecting (1), parallel (0), same line (infinite)
Polynomials & Factoring
Algebra- FOIL: (a+b)(c+d) = ac + ad + bc + bd
- Difference of squares: a² − b² = (a+b)(a−b)
- Factor by finding two numbers that multiply to c and add to b in x²+bx+c
Quadratic Equations
Advanced Algebra- Factor, complete the square, or use the quadratic formula
- Vertex form: y = a(x−h)² + k, vertex at (h,k)
- Discriminant b²−4ac: positive=2 solutions, zero=1, negative=0 real solutions
Functions & Function Notation
Advanced Algebra- f(x) notation: substitute x-value to evaluate
- Domain (valid inputs), range (possible outputs)
- Composite functions: (f∘g)(x) = f(g(x))
- Inverse functions: swap x and y, then solve for y
Coordinate Geometry
Geometry- Slope: m = (y₂−y₁)/(x₂−x₁)
- Midpoint: ((x₁+x₂)/2, (y₁+y₂)/2)
- Distance: d = √((x₂−x₁)² + (y₂−y₁)²)
- Parallel lines have equal slopes; perpendicular lines have slopes that are negative reciprocals
Triangles & Polygons
Geometry- Interior angles of a triangle sum to 180°
- Pythagorean theorem: a² + b² = c²
- Common triples: 3-4-5, 5-12-13, 8-15-17
- Special right triangles: 45-45-90 (sides x, x, x√2) and 30-60-90 (sides x, x√3, 2x)
Circles
Geometry- Area = πr², Circumference = 2πr
- Arc length = (central angle / 360°) × 2πr
- Sector area = (central angle / 360°) × πr²
- Standard form of circle equation: (x−h)² + (y−k)² = r²
Trigonometry
Geometry- SOH-CAH-TOA: sin=opp/hyp, cos=adj/hyp, tan=opp/adj
- Unit circle: key angles 30°, 45°, 60°, 90° and their radian equivalents
- Law of Sines and Law of Cosines for non-right triangles
- Trig identities: sin²θ + cos²θ = 1
Statistics & Data Interpretation
Statistics & Probability- Mean = sum / count; Median = middle value; Mode = most frequent
- Outliers pull the mean but not the median
- Standard deviation measures spread around the mean
- Read bar graphs, line graphs, scatterplots, and box plots
Probability & Counting
Statistics & Probability- P(event) = favorable outcomes / total outcomes
- P(A and B) = P(A) × P(B) for independent events
- P(A or B) = P(A) + P(B) − P(A and B)
- Permutations: nPr = n!/(n−r)! | Combinations: nCr = n!/[r!(n−r)!]
Matrices & Vectors
Number & Quantity- Matrix addition: add corresponding elements
- Matrix multiplication: row × column (dimensions must be compatible)
- Scalar multiplication: multiply every element by the scalar
- Vectors: magnitude = √(a²+b²); add vectors component-wise
ACT Math: 5 High-Impact Strategies
- Work in order, but skip and return. Questions 1–20 are mostly straightforward; skip hard ones and come back to protect easy points.
- Plug in numbers. When a question uses variables in the answer choices, substitute a simple number (like 2 or 3) and see which answer matches.
- Back-solve from answer choices. Try the middle answer choice (C or J) first. If too big/small, you know which direction to adjust.
- Draw and label diagrams. Always sketch geometry problems. Label all given information directly on the figure.
- Watch units and re-read the question. The ACT often asks for something other than what you naturally compute (e.g., asks for area when you computed perimeter).
Reading Section
40 questions · 35 minutes · 4 passages (1 paired)
Passages: Literary Narrative, Social Science, Humanities, and Natural Science — always in this order.
Main Idea & Central Theme
Key Ideas & Details — 55-60%Asks you to identify the primary purpose, main idea, or central argument of a passage or paragraph. The correct answer covers the whole passage — not just one part.
Example Question
The main idea of the passage is best described as:
Strategy Tip
Read the first and last paragraphs carefully — they frame the main idea. Eliminate answers that are too specific (one detail) or too broad (not mentioned).
Supporting Details
Key Ideas & Details — 55-60%Asks you to locate specific information stated in the passage. The answer is directly in the text — these are pure retrieval questions.
Example Question
According to the passage, what reason does the author give for the decline in pollinator populations?
Strategy Tip
Go back to the passage and find the exact lines. The correct answer will be a close paraphrase of what is stated, not an inference. Beware of choices that sound plausible but change the meaning.
Inference & Implication
Key Ideas & Details — 55-60%Asks what the author implies or what can be logically concluded based on information in the passage — not explicitly stated, but clearly supported.
Example Question
It can reasonably be inferred from the passage that the author believes urban farming will:
Strategy Tip
The correct inference must be grounded in evidence from the passage — not common knowledge, not personal opinion. If you cannot point to a passage sentence that supports it, it's probably wrong.
Cause and Effect
Key Ideas & Details — 55-60%Tests understanding of causal relationships — what led to what — and sequence of events described in the passage.
Example Question
Based on the passage, what was the primary cause of the shift in agricultural practices described in the third paragraph?
Strategy Tip
Look for signal words: 'because,' 'therefore,' 'as a result,' 'consequently,' 'led to.' Trace the causal chain in the passage before selecting your answer.
Vocabulary in Context
Craft & Structure — 25-30%Asks for the meaning of a word or phrase as used in a specific part of the passage. Context always determines meaning — not the most common dictionary definition.
Example Question
As it is used in line 37, the word 'cultivated' most nearly means:
Strategy Tip
Substitute each answer choice into the sentence. The correct answer preserves the original meaning. Watch for choices that are valid definitions of the word but do not fit the specific context.
Author's Purpose & Tone
Craft & Structure — 25-30%Tests why the author wrote the passage or included a specific detail, and what perspective or emotional stance the author brings to the subject.
Example Question
The author most likely includes the anecdote in paragraph 2 in order to:
Strategy Tip
Ask: what job does this part do? Does it provide evidence, illustrate a contrast, create empathy, or establish credibility? Tone words: objective, critical, nostalgic, sardonic, reverent.
Text Structure & Organization
Craft & Structure — 25-30%Asks how the passage or a section of it is organized — chronologically, by comparison, problem-solution, cause-effect, or order of importance.
Example Question
The overall structure of the passage can best be described as:
Strategy Tip
Skim each paragraph's opening sentence to map the passage structure. Common patterns: claim-then-evidence, chronological narrative, problem-solution, compare-contrast.
Comparing Paired Passages
Integration of Knowledge — 13-18%One of the four passage sets uses two shorter passages (A and B) on the same topic. Questions ask you to compare viewpoints, evidence, and rhetorical approaches.
Example Question
Unlike the author of Passage A, the author of Passage B suggests that:
Strategy Tip
Summarize each author's main claim in one sentence before tackling comparison questions. Focus on: where they agree, where they disagree, what evidence each uses.
Function of a Specific Detail
Craft & Structure — 25-30%Asks why the author included a specific example, quotation, anecdote, or statistic and what rhetorical purpose it serves in the argument.
Example Question
The author mentions the 2022 study (lines 45-48) primarily to:
Strategy Tip
Identify what the surrounding paragraph is arguing. Then determine whether the detail proves, illustrates, qualifies, or counters that argument.
Evaluating Arguments
Integration of Knowledge — 13-18%Asks you to assess the strength of an argument, identify unstated assumptions, or determine whether a conclusion is supported by the evidence.
Example Question
Which of the following, if true, would most weaken the author's central argument?
Strategy Tip
Identify the author's conclusion and the evidence supporting it. A weakener introduces information that breaks the link between evidence and conclusion.
Passage Type Strategies
- Literary Narrative: Pay attention to character relationships and tone shifts. Inference questions dominate.
- Social Science: Identify the author's argument early. Look for bias and supporting evidence.
- Humanities: Often a personal essay or cultural analysis. Tone and author perspective are heavily tested.
- Natural Science: Read for the main claims. Vocabulary-in-context is common here.
Eliminating Wrong Answers
- Too extreme: Choices with "never," "always," "completely," "all" are usually wrong.
- Too specific: Answers about a single detail when main idea is asked.
- Contradicts the passage: Any answer that reverses the passage's meaning.
- Outside knowledge: Answers that sound true but are not in the passage.
Science Section
40 questions · 35 minutes · 6–7 passages
Tests data interpretation, experimental analysis, and scientific reasoning. Memorized science facts are rarely needed.
Reading Tables & Graphs
Data Representation — 30-40%Presents graphs, tables, scatterplots, or diagrams. Asks you to read a specific value, identify a maximum or minimum, or describe the shape of data. No science knowledge required.
Example Question
Based on Figure 1, at what temperature did the reaction rate reach its maximum?
Strategy Tip
Read axis labels and units first. Trace your finger along the data to find the answer. Most questions can be answered by careful reading — no outside science knowledge needed.
Identifying Trends & Relationships
Data Representation — 30-40%Asks whether a relationship between two variables is direct (both increase), inverse (one up, one down), or shows no clear pattern. Tests your ability to describe the shape of data.
Example Question
Based on Table 1, as the concentration of Solution X increased, the pH of the mixture:
Strategy Tip
Look at two columns and ask: does one go up as the other goes up (direct) or down (inverse)? If the pattern is inconsistent, look for 'no clear relationship.'
Interpolation & Extrapolation
Data Representation — 30-40%Asks you to estimate a value between data points (interpolation) or predict a value beyond the measured range (extrapolation) using the observed trend.
Example Question
Based on the trend in Figure 2, what would the reaction rate most likely be at a concentration of 0.8 M?
Strategy Tip
For interpolation: identify the trend between adjacent data points and estimate proportionally. For extrapolation: extend the trend line but acknowledge it may not hold indefinitely.
Understanding Experimental Design
Research Summaries — 45-55%Describes one or more experiments and asks about the purpose, procedure, and variables (independent, dependent, controlled). Tests your ability to analyze how an experiment was structured.
Example Question
In Experiment 2, what was the independent variable?
Strategy Tip
Independent variable = what the scientist intentionally changes. Dependent variable = what is measured. Controlled variables = kept constant. Read the full experiment description before answering.
Analyzing Results & Drawing Conclusions
Research Summaries — 45-55%Asks what conclusions can be drawn from experimental results, whether a hypothesis is supported, or what would happen under modified conditions.
Example Question
Based on the results of Experiment 1, which hypothesis is best supported?
Strategy Tip
Match the data to the hypothesis. A supported hypothesis has predictions that match the observed results. If data contradicts the prediction, the hypothesis is not supported — even if it sounds scientifically reasonable.
Predicting New Experimental Results
Research Summaries — 45-55%Asks you to predict what would happen if an experiment were modified — a new variable added, a condition changed, or the procedure extended beyond the data range.
Example Question
If Experiment 1 were repeated at 50°C instead of 30°C, the reaction rate would most likely:
Strategy Tip
Identify the existing trend in the data, then extend it logically to the new condition. If a plateau or reversal is shown, factor that in — do not assume the trend continues indefinitely.
Comparing Conflicting Viewpoints
Conflicting Viewpoints — 15-20%Presents two or more scientists with different explanations for the same phenomenon. Questions ask you to identify agreements, disagreements, and the core assumption of each position.
Example Question
Scientist 1 and Scientist 2 would most likely agree that:
Strategy Tip
Read each viewpoint separately and write a one-sentence summary before answering. Most questions hinge on where they agree, where they disagree, and what evidence would change one scientist's mind.
Evaluating Evidence Against a Viewpoint
Conflicting Viewpoints — 15-20%Asks which new piece of evidence would strengthen or weaken a particular scientist's viewpoint, or which viewpoint is better supported by new data.
Example Question
Which of the following findings, if true, would most weaken Scientist 2's hypothesis?
Strategy Tip
Identify the core claim of the viewpoint first. A weakener provides evidence that directly contradicts the viewpoint's central prediction. A strengthener provides evidence that confirms it.
Variable Types: Quick Reference
| Variable Type | Definition | How to Identify It | Example |
|---|---|---|---|
| Independent Variable | The variable the experimenter intentionally changes | Different across trials; often the x-axis of a graph | Different pH levels (3, 5, 7, 9, 11) in enzyme experiment |
| Dependent Variable | The outcome that is measured as a result | What the researcher records; often the y-axis | Reaction rate (mg/min) measured after 10 minutes |
| Controlled Variable | A variable kept constant to ensure a fair test | Everything held the same across all trials | Temperature fixed at 37°C across all pH trials |
| Control Group | The baseline group receiving no treatment or standard conditions | Serves as a comparison point for the experimental groups | Enzyme experiment at pH 7 (body pH) if testing extreme conditions |
See These Question Types in Action
Practice with 42 realistic sample questions — complete with full explanations for every answer.