Exercises
Practise with the tools. Open an exercise, work on it in the tool, then check your answer. The same engine that powers the tools checks every attempt, so there are no answer keys to look up.
Exercise sets
- Truth table10 exercisesTruth tables: formulas, pairs and setsFill in full truth tables to classify single formulas, compare pairs of formulas, and test sets for consistency.0 of 10 solved
- Truth table10 exercisesTruth tables: testing argumentsDecide with a full truth table whether each argument is valid, from familiar patterns to three-letter cases.0 of 10 solved
- Tableau10 exercisesTableaux: formulas, pairs and setsBuild tableaux to decide whether a formula is a tautology, whether two formulas are equivalent, and whether a set is consistent.0 of 10 solved
- Tableau10 exercisesTableaux: testing argumentsTest arguments with a tableau: close every branch for a valid argument, or find an open branch that gives a counterexample.0 of 10 solved
- Proof10 exercisesProofs: conjunction and disjunctionFitch proofs with conjunction and disjunction: introduction and elimination, and reasoning by cases.0 of 10 solved
- Proof10 exercisesProofs: the conditionalFitch proofs with the conditional: eliminate it by modus ponens, and introduce it by assuming the antecedent in a subproof.0 of 10 solved
- Proof10 exercisesProofs: negation and absurdityFitch proofs with negation and the absurdity sign, using only the basic rules: negation introduction, indirect proof, and explosion.0 of 10 solved
- Proof10 exercisesProofs: derived rulesFitch proofs where the derived rules may be cited: disjunctive syllogism, modus tollens, double negation elimination, excluded middle, and De Morgan.0 of 10 solved
Random practice
A fresh problem for any tool. The settings and the seed are part of the address, so you can share exactly the same problem.
Tool
Difficulty
Choose a tool and a difficulty, then ask for a problem.