Truth Table Flashcards: Connectives & Logical Equivalence

84 truth-table flashcards on logical connectives, material conditionals, nested expressions, equivalence, and counterexamples, with short explanations.

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Practice propositional logic with 84 English truth-table flashcards. The set covers NOT (¬), AND (∧), inclusive OR (∨), exclusive OR (⊕), the material conditional (→), and the biconditional (↔). T means true and F means false. It suits learners starting formal logic or discrete mathematics.

Cards ask you to recall a connective’s truth conditions, identify a connective from its full rule, evaluate an expression from a stated assignment, and produce short output columns with an explicit row order. A few original statement-to-symbol tasks and one symbol-to-statement task connect the notation to English. Later cards practice De Morgan’s laws, double negation, conditional rewriting, biconditional and XOR expansions, negated conditionals, and the distinction between a conditional, its converse, inverse, and contrapositive.

The sequence introduces notation and simple connectives before nested expressions, logical equivalence, counterexamples, and tautology/contradiction/contingency classification. Selected equivalences have separate forward and reverse cards, placed apart. Answers start with the result and give a short reason. For a counterexample task, any assignment that makes the two outputs differ is a valid answer.

This is a focused practice set, not a full logic course or an exam syllabus. It excludes quantified statements, proof systems, circuits, and programming-language evaluation rules. It does not ask for a connective from a lone truth value, which would be ambiguous, or repeat every possible symbolic and English permutation. Material implication is used as a truth-functional rule; the cards do not treat it as a theory of causation or every everyday use of “if”.

For a short introduction, read truth values, conjunction and disjunction. For study habits, see how to use flashcards for math.

The questions, answers, examples, order, metadata, and cover were independently created with AI assistance. Logic facts were checked against the open textbook forall x: Calgary, especially its chapters on connective truth tables, complete truth tables, and semantic concepts, and by direct truth-value calculation. No textbook exercises, teaching prose, diagrams, examination questions, or competitor cards were copied. The original text and generated cover are released under CC0 1.0 to the extent applicable rights exist; reference-source text retains its own license. This is an independent resource, unaffiliated with the Open Logic Project or any school or examination provider.

Cartões deste baralho

  1. Cartão 1

    Pergunta

    In classical propositional logic, what is a proposition?

    Resposta

    A statement with a truth value: true or false. A question or command is not a proposition in this setting.

  2. Cartão 2

    Pergunta

    What does negation (¬p) do to the truth value of p?

    Resposta

    It reverses it: true becomes false, and false becomes true.

  3. Cartão 3

    Pergunta

    When is the conjunction (p ∧ q) true?

    Resposta

    Only when p and q are both true.

  4. Cartão 4

    Pergunta

    When is the inclusive disjunction (p ∨ q) true?

    Resposta

    When at least one of p and q is true, including when both are true.

  5. Cartão 5

    Pergunta

    What does one valuation assign in a propositional truth table?

    Resposta

    One truth value to each proposition letter. The assignment stays fixed throughout that row.

  6. Cartão 6

    Pergunta

    When is the material conditional (p → q) false?

    Resposta

    Only when p is true and q is false. Here p is the antecedent and q is the consequent.

  7. Cartão 7

    Pergunta

    When is the biconditional (p ↔ q) true?

    Resposta

    When p and q have the same truth value: both true or both false.

  8. Cartão 8

    Pergunta

    When is exclusive OR (p ⊕ q) true?

    Resposta

    When exactly one of p and q is true. It is false when their truth values match.

  9. Cartão 9

    Pergunta

    What is the main connective in ((¬p) ∧ q)?

    Resposta

    ∧ (AND). It combines the whole left part, (¬p), with q.

  10. Cartão 10

    Pergunta

    How many rows does a complete truth table with three distinct proposition letters need?

    Resposta

    8 rows: each of the three letters has two choices, so 2³ = 8.

  11. Cartão 11

    Pergunta

    If p = F, what is (¬p)?

    Resposta

    T. Negation reverses F to T.

  12. Cartão 12

    Pergunta

    If p = T and q = F, what is (p ∧ q)?

    Resposta

    F. AND needs both inputs to be true.

  13. Cartão 13

    Pergunta

    If p = T and q = T, what is inclusive OR (p ∨ q)?

    Resposta

    T. Inclusive OR allows both inputs to be true.

  14. Cartão 14

    Pergunta

    If p = T and q = T, what is the material conditional (p → q)?

    Resposta

    T. A true antecedent with a true consequent does not make the conditional false.

  15. Cartão 15

    Pergunta

    If p = F and q = F, what is (p ↔ q)?

    Resposta

    T. The two truth values match, even though neither is true.

  16. Cartão 16

    Pergunta

    If p = T and q = T, what is exclusive OR (p ⊕ q)?

    Resposta

    F. XOR requires exactly one true input.

  17. Cartão 17

    Pergunta

    Does a true material conditional (p → q) establish that p causes q?

    Resposta

    No. Material implication is determined by truth values; it does not establish causation or capture every everyday use of “if”.

  18. Cartão 18

    Pergunta

    What assignments are listed by the two-letter row order TT, TF, FT, FF?

    Resposta

    (p, q) = (T, T), (T, F), (F, T), (F, F). Each possible assignment appears once.

  19. Cartão 19

    Pergunta

    In ¬(p ∨ q), does ¬ negate just p or the whole disjunction?

    Resposta

    The whole disjunction (p ∨ q). Evaluate that parenthesized expression before negating it.

  20. Cartão 20

    Pergunta

    If p = F and q = T, what is the material conditional (p → q)?

    Resposta

    T. A material conditional with a false antecedent is true.

  21. Cartão 21

    Pergunta

    If p = T and q = F, what is (p ↔ q)?

    Resposta

    F. The two truth values differ.

  22. Cartão 22

    Pergunta

    If p = T and q = F, what is exclusive OR (p ⊕ q)?

    Resposta

    T. Exactly one input is true.

  23. Cartão 23

    Pergunta

    Which standard connective is true exactly when both inputs are true?

    Resposta

    Conjunction (AND), written ∧.

  24. Cartão 24

    Pergunta

    Which standard connective is false exactly when both inputs are false?

    Resposta

    Inclusive disjunction (OR), written ∨. The both-true case is true.

  25. Cartão 25

    Pergunta

    Which standard connective takes one input and reverses its truth value?

    Resposta

    Negation (NOT), written ¬.

  26. Cartão 26

    Pergunta

    If p = F and q = F, what is the material conditional (p → q)?

    Resposta

    T. Its only false case requires a true antecedent and a false consequent.

  27. Cartão 27

    Pergunta

    Which standard connective is true exactly when its two inputs have matching truth values?

    Resposta

    The biconditional (if and only if), written ↔.

  28. Cartão 28

    Pergunta

    Which standard connective is true exactly when its two inputs have different truth values?

    Resposta

    Exclusive OR (XOR), written ⊕.

  29. Cartão 29

    Pergunta

    What is the main connective in ((p ∨ q) → (¬r))?

    Resposta

    → (the material conditional). The entire disjunction is the antecedent, and (¬r) is the consequent.

  30. Cartão 30

    Pergunta

    Which standard connective is false exactly when its first input is true and its second input is false?

    Resposta

    The material conditional, written →. Input order matters.

  31. Cartão 31

    Pergunta

    Give the output column for (p ∧ q), with (p, q) rows TT, TF, FT, FF.

    Resposta

    T, F, F, F. Only the both-true row satisfies AND.

  32. Cartão 32

    Pergunta

    If p = T and q = F, what is ¬(p ∧ q)?

    Resposta

    T. First (p ∧ q) is F; negating it gives T.

  33. Cartão 33

    Pergunta

    Let a mean “the archive is open” and b mean “the desk is staffed”. Symbolize “the archive is open and the desk is staffed”.

    Resposta

    (a ∧ b). Both statements are asserted.

  34. Cartão 34

    Pergunta

    Give the output column for the material conditional (p → q), with (p, q) rows TT, TF, FT, FF.

    Resposta

    T, F, T, T. Only the true-antecedent, false-consequent row fails.

  35. Cartão 35

    Pergunta

    What makes a formula a tautology in classical propositional logic?

    Resposta

    It is true on every possible valuation, not just the row currently being checked.

  36. Cartão 36

    Pergunta

    Give the output column for inclusive OR (p ∨ q), with (p, q) rows TT, TF, FT, FF.

    Resposta

    T, T, T, F. Only the both-false row fails inclusive OR.

  37. Cartão 37

    Pergunta

    When are two propositional formulas logically equivalent?

    Resposta

    When their final truth values match on every valuation of their combined proposition letters.

  38. Cartão 38

    Pergunta

    Give the output column for (p ↔ q), with (p, q) rows TT, TF, FT, FF.

    Resposta

    T, F, F, T. The first and last rows have matching truth values.

  39. Cartão 39

    Pergunta

    If p = F and q = T, what is (p ∨ (¬q)), using inclusive OR?

    Resposta

    F. Both p and (¬q) are F.

  40. Cartão 40

    Pergunta

    If p = T and q = F, what is the material conditional (p → q)?

    Resposta

    F. This is its only false input combination.

  41. Cartão 41

    Pergunta

    Give the output column for (¬p), with p rows T, F.

    Resposta

    F, T. Negation reverses each row.

  42. Cartão 42

    Pergunta

    Let s mean “the scan succeeds” and a mean “the alert appears”. Symbolize “if the scan succeeds, the alert appears”, using material implication.

    Resposta

    (s → a). The scan statement is the antecedent; the alert statement is the consequent.

  43. Cartão 43

    Pergunta

    Give the output column for exclusive OR (p ⊕ q), with (p, q) rows TT, TF, FT, FF.

    Resposta

    F, T, T, F. Exactly one input is true in the middle two rows.

  44. Cartão 44

    Pergunta

    What makes a formula a contradiction in classical propositional logic?

    Resposta

    It is false on every possible valuation.

  45. Cartão 45

    Pergunta

    If p = T, q = F and r = T, what is ((p ∧ q) ∨ r), using inclusive OR?

    Resposta

    T. The conjunction is F, but r is T, so the disjunction is T.

  46. Cartão 46

    Pergunta

    Simplify ¬(¬p) without changing its truth value.

    Resposta

    p. Two negations restore the original truth value.

  47. Cartão 47

    Pergunta

    Let d mean “the door is unlocked” and c mean “the code is accepted”. Symbolize “the door is unlocked if and only if the code is accepted”.

    Resposta

    (d ↔ c). Both directions of the conditional are required.

  48. Cartão 48

    Pergunta

    What makes a propositional formula contingent?

    Resposta

    It is true on at least one valuation and false on at least one other valuation.

  49. Cartão 49

    Pergunta

    If p = T and q = T, what is (p → (¬q)), using material implication?

    Resposta

    F. Its antecedent is T and its consequent (¬q) is F.

  50. Cartão 50

    Pergunta

    Use De Morgan’s law to rewrite ¬(p ∧ q) with negations only on letters.

    Resposta

    ((¬p) ∨ (¬q)). At least one conjunct must be false; ∨ is inclusive OR.

  51. Cartão 51

    Pergunta

    Let n mean “the north path is open” and e mean “the east path is open”. Symbolize “at least one of these paths is open, possibly both”.

    Resposta

    (n ∨ e). This is inclusive OR.

  52. Cartão 52

    Pergunta

    Classify (p ∨ (¬p)): tautology, contradiction or contingent? Use classical logic and inclusive OR.

    Resposta

    Tautology. Whether p is T or F, one disjunct is T.

  53. Cartão 53

    Pergunta

    If p = F and q = F, what is ¬(p ∨ q), using inclusive OR?

    Resposta

    T. The disjunction is F, so its negation is T.

  54. Cartão 54

    Pergunta

    Use De Morgan’s law to rewrite ¬(p ∨ q) with negations only on letters. Use inclusive OR.

    Resposta

    ((¬p) ∧ (¬q)). Both disjuncts must be false.

  55. Cartão 55

    Pergunta

    Let w mean “the window is closed” and h mean “the heater is on”. Read (h → w) as an English material conditional.

    Resposta

    If the heater is on, then the window is closed. The formula itself makes no causal claim.

  56. Cartão 56

    Pergunta

    Classify (p ∧ (¬p)): tautology, contradiction or contingent?

    Resposta

    Contradiction. The two conjuncts cannot both be true on any valuation.

  57. Cartão 57

    Pergunta

    Rewrite the material conditional (p → q) using only NOT and inclusive OR.

    Resposta

    ((¬p) ∨ q). It is false exactly when p is T and q is F.

  58. Cartão 58

    Pergunta

    If p = T, q = T and r = F, what is ((p ⊕ q) ↔ r), where ⊕ is exclusive OR?

    Resposta

    T. The XOR is F and r is F, so the biconditional compares matching values.

  59. Cartão 59

    Pergunta

    Write an expression with exactly two NOT operators that is equivalent to p.

    Resposta

    ¬(¬p). Negating twice leaves every truth value unchanged.

  60. Cartão 60

    Pergunta

    Classify (p ∧ q): tautology, contradiction or contingent?

    Resposta

    Contingent. It is T at p = T, q = T and F at p = F, q = T.

  61. Cartão 61

    Pergunta

    What is the contrapositive of the material conditional (p → q)?

    Resposta

    ((¬q) → (¬p)). Swap the two sides and negate both.

  62. Cartão 62

    Pergunta

    Rewrite ¬(p → q) using AND and NOT, with → meaning material implication.

    Resposta

    (p ∧ (¬q)). A material conditional fails exactly when its antecedent is true and its consequent is false.

  63. Cartão 63

    Pergunta

    Rewrite ((¬p) ∨ (¬q)) as one negation of a conjunction, using inclusive OR.

    Resposta

    ¬(p ∧ q). This is De Morgan’s law in the reverse direction.

  64. Cartão 64

    Pergunta

    Give the output column for (p ∨ (¬q)), with (p, q) rows TT, TF, FT, FF and inclusive OR.

    Resposta

    T, T, F, T. The only false row has p = F and q = T.

  65. Cartão 65

    Pergunta

    What is the converse of (p → q)?

    Resposta

    (q → p). Swap the antecedent and consequent without negating either.

  66. Cartão 66

    Pergunta

    Rewrite (p ↔ q) as an AND of two material conditionals.

    Resposta

    ((p → q) ∧ (q → p)). Both directions must hold.

  67. Cartão 67

    Pergunta

    Rewrite ((¬p) ∧ (¬q)) as one negation of an inclusive disjunction.

    Resposta

    ¬(p ∨ q). This is De Morgan’s law in the reverse direction.

  68. Cartão 68

    Pergunta

    Give one valuation showing that (p ∨ q) and (p ∧ q) are not equivalent. Use inclusive OR.

    Resposta

    p = T, q = F gives T for the OR and F for the AND. The swapped assignment also works.

  69. Cartão 69

    Pergunta

    What is the inverse of (p → q)?

    Resposta

    ((¬p) → (¬q)). Negate both sides without swapping them.

  70. Cartão 70

    Pergunta

    Rewrite ((¬p) ∨ q) as a single material conditional, using inclusive OR.

    Resposta

    (p → q). Both expressions fail exactly when p is T and q is F.

  71. Cartão 71

    Pergunta

    Rewrite exclusive OR (p ⊕ q) using AND, inclusive OR and NOT.

    Resposta

    ((p ∨ q) ∧ ¬(p ∧ q)). Require at least one true input and rule out both being true.

  72. Cartão 72

    Pergunta

    A formula is true for p = T and q = F. Is that enough to call it a tautology?

    Resposta

    No. A tautology must be true on every valuation. One true row establishes only that it can be true.

  73. Cartão 73

    Pergunta

    Is a material conditional (p → q) logically equivalent to its contrapositive ((¬q) → (¬p))?

    Resposta

    Yes. Both are false exactly when p is T and q is F.

  74. Cartão 74

    Pergunta

    Give one valuation showing that (p → q) and its converse (q → p) are not equivalent. Use material implication.

    Resposta

    p = T, q = F. Then (p → q) is F and (q → p) is T.

  75. Cartão 75

    Pergunta

    Rewrite ((p → q) ∧ (q → p)) using one connective, with both arrows meaning material implication.

    Resposta

    (p ↔ q). This is the biconditional.

  76. Cartão 76

    Pergunta

    What does one valuation with different outputs prove about two formulas?

    Resposta

    They are not logically equivalent. Equivalence requires agreement on every valuation.

  77. Cartão 77

    Pergunta

    Give one valuation showing that (p → q) and its inverse ((¬p) → (¬q)) are not equivalent. Use material implication.

    Resposta

    p = T, q = F. The original is F, while the inverse has a false antecedent and is T.

  78. Cartão 78

    Pergunta

    Give one valuation showing that ¬(p ∧ q) and ((¬p) ∧ (¬q)) are not equivalent.

    Resposta

    p = T, q = F. The negated conjunction is T; the conjunction of negations is F.

  79. Cartão 79

    Pergunta

    Which connective does ((p ∨ q) ∧ ¬(p ∧ q)) express? Here ∨ is inclusive OR.

    Resposta

    Exclusive OR: (p ⊕ q). Exactly one input must be true.

  80. Cartão 80

    Pergunta

    If (p ↔ q) is true on one row, does that show that the formulas p and q are logically equivalent?

    Resposta

    No. They match on that row only. Logical equivalence requires the biconditional to be true on every valuation.

  81. Cartão 81

    Pergunta

    Are the converse (q → p) and inverse ((¬p) → (¬q)) of (p → q) equivalent to each other? Use material implication.

    Resposta

    Yes. They are contrapositives of each other, and both are false exactly when q is T and p is F.

  82. Cartão 82

    Pergunta

    At p = T, q = F and r = F, compare ((p ∨ q) ∧ r) with (p ∨ (q ∧ r)). Use inclusive OR.

    Resposta

    The first is F; the second is T. Parentheses change which operations combine first.

  83. Cartão 83

    Pergunta

    Rewrite (p ∧ (¬q)) as the negation of one material conditional.

    Resposta

    ¬(p → q). The conjunction describes exactly the conditional’s false case.

  84. Cartão 84

    Pergunta

    Among AND (∧), inclusive OR (∨), XOR (⊕), material conditional (→) and biconditional (↔), which has outputs T, F, F, T for (p, q) rows TT, TF, FT, FF?

    Resposta

    Biconditional (↔). It is true on the two rows where the inputs match.

The AND, OR and NOT symbols on a navy study tile, with light and dark tokens on an ivory background.

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Truth Table Flashcards: Connectives & Logical Equivalence

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