Practical lesson: logical operations
Answers are for parents and teachers.
1
Build the truth table of ¬A ∨ ¬B (rows 11, 10, 01, 00). Which expression is it equal to?
0, 1, 1, 1; it equals ¬(A ∧ B).
2
Build the truth table of A ∧ (A ∨ B). Which expression is it equal to?
1, 1, 0, 0; it equals A.
3
With A = 0, B = 0, C = 1 evaluate ¬(A ∨ B) ∧ C.
1
4
Each of A and B is a truth-teller or a liar. A says “B is a liar”, and B says “We are both truth-tellers”. Who are they?
If B were a truth-teller, A would be one too and A’s sentence (“B is a liar”) would be false – a contradiction. So B is a liar, A’s sentence is true, and A is a truth-teller.