← Math: Logic and Proofs

⇄ Sync
Length

Program
History and progress transfer
Choose a topic — problems will keep coming one after another for as long as you like

Theory of all steps of the program by blocks. Open a topic to read it.

How a session goes

A session is 10–90 minutes: a warm-up on what you've learned, new steps with short theory and problems, practice. Each problem gives two tries: 100 points on the first, 60 on the second; after the second mistake the correct answer is shown. You move on in the program if 70 % of the problems are solved.

Problems with numbers are generated anew every time a step is repeated. A fractional answer can be entered with a comma, a point or as a fraction: 0,5, 0.5, 1/2. In Practice any topic is available without a timer.

About the course

Statements and connectives, implication, truth tables, equivalence and De Morgan's laws, the quantifiers ∀ and ∃, sets, necessary and sufficient conditions, the converse; proofs: direct, by contradiction, counterexample, induction, the pigeonhole principle. Grade 7–8 math is enough.

Course program: 28 lessons

Statements and connectives

  1. What a proposition is
  2. AND, OR, NOT
  3. Implication: if…, then…
  4. Connectives: more
  5. Checkpoint: statements and connectives

Truth tables and equivalence

  1. Truth tables
  2. Equivalent formulas
  3. Negation: De Morgan's laws
  4. Negations: more
  5. Checkpoint: tables and equivalence

Quantifiers and sets

  1. The quantifiers ∀ and ∃
  2. Sets and operations
  3. Sets and quantifiers: more
  4. Checkpoint: quantifiers and sets

How theorems are built

  1. Necessary and sufficient conditions
  2. Converse and inverse statements
  3. Conditions and converses: more
  4. Checkpoint: theorems and conditions

Methods of proof

  1. Direct proof
  2. Proof by contradiction
  3. Counterexample
  4. Proofs: more
  5. Checkpoint: methods of proof

Induction and the pigeonhole principle

  1. Mathematical induction
  2. Induction: more
  3. The pigeonhole principle
  4. The pigeonhole principle: more
  5. Checkpoint: induction and the pigeonhole principle