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.

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
pqr(r ↔ (q ↔ p)) → (¬q ∨ r)111110101100011010001000

Exactly one row of the truth table makes (r ↔ (q ↔ p)) → (¬q ∨ r) false. Click that row.

(r ↔ (q ↔ p)) → (¬q ∨ r)
  1. 1p = 1, q = 1, r = 1
  2. 2p = 1, q = 1, r = 0
  3. 3p = 1, q = 0, r = 1
  4. 4p = 1, q = 0, r = 0
  5. 5p = 0, q = 1, r = 1
  6. 6p = 0, q = 1, r = 0
  7. 7p = 0, q = 0, r = 1
  8. 8p = 0, q = 0, r = 0
2.Easy

The complete truth table of ¬((r ∧ p) → (q ∨ (q → p))) is written out. In how many rows N is p = 1 and r = 0?

¬((r ∧ p) → (q ∨ (q → p)))
N =
3.Medium
(p → r) → qp ∧ (r → q)(p → q) ∧ (r → q)p → (r → q)

Which formula is logically equivalent to (p ∧ r) → q? Click it.

(p ∧ r) → q
  1. 1(p → r) → q
  2. 2p ∧ (r → q)
  3. 3(p → q) ∧ (r → q)
  4. 4p → (r → q)
4.Medium
pqrp ∨ (¬r ↔ p)r → q(p ∨ (¬r ↔ p)) ∧ (r → q)111?110?101?100?011?010?001?000?

In how many of the 8 rows of its truth table is (p ∨ (¬r ↔ p)) ∧ (r → q) true? Call this number N.

(p ∨ (¬r ↔ p)) ∧ (r → q)
N =
5.Hard
r → pp → r¬r → ¬pr ∧ p

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

r → qq → p
  1. 1r → p
  2. 2p → r
  3. 3¬r → ¬p
  4. 4r ∧ p
6.Hard
∀x (¬P(x) → ¬Q(x))∀x (P(x) → ¬Q(x))∀x (P(x) ∧ ¬Q(x))∃x (P(x) ∧ ¬Q(x))

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

¬∃x (P(x) → Q(x))
  1. 1∀x (¬P(x) → ¬Q(x))
  2. 2∀x (P(x) → ¬Q(x))
  3. 3∀x (P(x) ∧ ¬Q(x))
  4. 4∃x (P(x) ∧ ¬Q(x))

Answer key

  1. 1. p = 0, q = 1, r = 0
  2. 2. N = 2
  3. 3. p → (r → q)
  4. 4. N = 4
  5. 5. r → p
  6. 6. ∀x (P(x) ∧ ¬Q(x))

Full step-by-step solutions: practise this topic on examproblems.com.