Free Congruence Modulo n Calculator - Given a possible congruence relation a ≡ b (mod n), this determines if the relation holds true (b is congruent to c modulo n).

Free True False Equations Calculator - Determines if a set of addition and subtraction of numbers on each side of an equation are equivalent. Also known as true or false equations

Free Truth Tables Calculator - Sets up a truth table based on a logical statement of 1, 2 or 3 letters with statements such as propositions, equivalence, conjunction, disjunction, negation. Includes modus ponens.

Free Unknown Number Calculator - Determines the unknown number needed to make an equation true.