Propositional logic & proofs worksheet with answers

Free printable Propositional logic & proofs worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
abc(¬a ↔ b) → (c ↔ (b ∧ c))111110101100011010001000

Exactly one row of the truth table makes (¬a ↔ b) → (c ↔ (b ∧ c)) false. Click that row.

(¬a ↔ b) → (c ↔ (b ∧ c))
  1. 1a = 1, b = 1, c = 1
  2. 2a = 1, b = 1, c = 0
  3. 3a = 1, b = 0, c = 1
  4. 4a = 1, b = 0, c = 0
  5. 5a = 0, b = 1, c = 1
  6. 6a = 0, b = 1, c = 0
  7. 7a = 0, b = 0, c = 1
  8. 8a = 0, b = 0, c = 0
2.Easy
pq(p → q) ↔ p11100100

Exactly one row of the truth table makes (p → q) ↔ p true. Click that row.

(p → q) ↔ p
  1. 1p = 1, q = 1
  2. 2p = 1, q = 0
  3. 3p = 0, q = 1
  4. 4p = 0, q = 0
3.Medium
r ↔ ¬q¬r ∨ ¬q¬r ↔ ¬qr ∧ ¬q

Which formula is logically equivalent to ¬(r ↔ q)? Click it.

¬(r ↔ q)
  1. 1r ↔ ¬q
  2. 2¬r ∨ ¬q
  3. 3¬r ↔ ¬q
  4. 4r ∧ ¬q
4.Medium
tautologycontradictioncontingency

Is (b → c) ∧ (b ∧ ¬c) a tautology, a contradiction or a contingency? Click your answer.

(b → c) ∧ (b ∧ ¬c)
  1. 1tautology
  2. 2contradiction
  3. 3contingency
5.Hard
q¬p ∧ q¬pp

The premises p → r; r → q; ¬q are given. Which conclusion follows from them? Click it.

p → rr → q¬q
  1. 1q
  2. 2¬p ∧ q
  3. 3¬p
  4. 4p
6.Hard
∀x A(x)∀x ¬A(x)∃x ¬A(x)∃x A(x)

Which statement is equivalent to ¬∃x A(x), with the negation moved all the way inside? Click it.

¬∃x A(x)
  1. 1∀x A(x)
  2. 2∀x ¬A(x)
  3. 3∃x ¬A(x)
  4. 4∃x A(x)

Answer key

  1. 1. a = 1, b = 0, c = 1
  2. 2. p = 1, q = 1
  3. 3. r ↔ ¬q
  4. 4. contradiction
  5. 5. ¬p
  6. 6. ∀x ¬A(x)

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