Categories

Problems - 3250 problems
- Algebra - 456 problems
  Absolute Value - 7 problems
  
  Absolute Value Of A Number (Other) - 1 problems
  
  Equations Containing Absoute Values - 1 problems
  
  Inequalities Containing Absolute Values - 4 problems
  
  Proof By Exhaustion - 1 problems
  
  Inequalities - 1 problems
  
  Algebraic Equations And Systems Of Equations - 63 problems
  
  Algebraic Equations And Systems Of Equations (Other) - 3 problems
  
  Binomial Theorem - 2 problems
  
  Diophantine Equations - 11 problems
  
  Higher Order Equations. Palindromic Polynomial Equations - 37 problems
  
  Equations Of Higher Order (Other) - 37 problems
  
  Systems Of Algebraic Non-Linear Equations - 1 problems
  
  Systems Of Linear Equations - 2 problems
  
  Algebraic Inequalities And Systems Of Inequalities - 25 problems
  
  Algebraic Inequalities (Other) - 5 problems
  
  Classical Inequalities - 3 problems
  
  Linear Inequalites And Systems Of Inequalities - 6 problems
  
  Number Inequalities. Number Comparison - 3 problems
  
  Quadratic Inequalites (Several Variables) - 6 problems
  
  Complex Numbers - 4 problems
  
  Cartesian Form Of A Complex Number, Complex Conjugate, Argand Diagram, Etc - 3 problems
  
  Diophantine Equations - 11 problems
  
  Discrete Mathematics - 1 problems
  
  Combinatorics - 1 problems
  
  Exponential Functions And Logarithms - 6 problems
  
  Exponential Functions And Logarithms (Other) - 4 problems
  
  Exponential Inequalities - 1 problems
  
  Fractions - 5 problems
  
  Simple Fractions - 3 problems
  
  Functional Equations - 13 problems
  
  Graphs And Locus Of Points On The Cartesian Plane - 18 problems
  
  Inequalities - 18 problems
  
  Mean Values - 54 problems
  
  Pascal Triangle - 14 problems
  
  Polynomials - 38 problems
  
  Algebraic Identities For Polynomials - 11 problems
  
  Factoring Polynomials - 6 problems
  
  Identical Transformations - 5 problems
  
  Cubic Polynomials - 1 problems
  
  Division Of Polynomials With Remainders. The Greatest Common Divisor (Gcd) And The Least Common Multiple (Lcm) For Polynomilas. - 3 problems
  
  Polynomial Remainder Theorem (Little Bezout'S Theorem). Factorisation. - 2 problems
  
  Polynomials(Other) - 3 problems
  
  Polynomials With Integer Coefficients And Integer Values - 3 problems
  
  Quadratic Polynomials - 11 problems
  
  Investigating The Quadratic Polynomial - 4 problems
  
  Quadratic Equations And Systems Of Equations - 2 problems
  
  Quadratic Equations. Formula For The Roots. - 1 problems
  
  Quadratic Equations. Vieta'S Rule. - 2 problems
  
  Symmetrical Polynomials - 1 problems
  
  Vieta'S Formulas - 1 problems
  
  Rational Functions - 5 problems
  
  Identical Transformations - 2 problems
  
  Inequalities. Method Of Intervals. - 1 problems
  
  Rational Equations - 2 problems
  
  Sequences - 66 problems
  
  Fibonacci - 11 problems
  
  Progressions - 12 problems
  
  Arithmetic Progression - 7 problems
  
  Geometric Progression - 5 problems
  
  Recurrence Relations - 1 problems
  
  Fibonacci Numbers - 1 problems
  
  Recurrent Relations - 30 problems
  
  Fibonacci Numbers - 10 problems
  
  Linear Recurrent Relations - 6 problems
  
  Recurrent Relations (Other) - 14 problems
  
  Sums Of Number Sequences And Difference Series - 2 problems
  
  Surds. Rational Powers - 12 problems
  
  Irrational Equations. - 7 problems
  
  Irrational Inequalities. - 3 problems
  
  Square Roots - 1 problems
  
  Trigonometry - 19 problems
  
  Identical Transformations (Trigonometry) - 3 problems
  
  Inverse Trigonometric Functions - 2 problems
  
  Systems Of Trigonometric Equations And Inequalities - 1 problems
  
  Trigonometrical Equations - 4 problems
  
  Trigonometrical Inequalities - 2 problems
  
  Trigonometry (Other) - 5 problems
- Algebra And Arithmetic - 74 problems
  Algebraic Geometry - 5 problems
  
  Cryptography - 5 problems
  
  Arithmetics. Mental Maths - 61 problems
  
  Rational And Irrational Numbers - 1 problems
- Algebraic Expressions - 2 problems
- Algorithm Theory - 1 problems
- Areas - 1 problems
- Arithmetic - 5 problems
- Arithmetic Puzzles - 6 problems
- Calculus - 221 problems
  Derivative - 27 problems
  
  Calculating A Derivative - 1 problems
  
  Convexity And Concavity - 2 problems
  
  Derivative And Extrema - 2 problems
  
  Derivative And Multiple Roots - 12 problems
  
  Derivative And Tangent Line - 2 problems
  
  Increasing And Decreasing. Researching Functions - 10 problems
  
  Functions Of One Variable. Continuity - 41 problems
  
  Certain Properties Of A Function And Recurrence Relations. - 12 problems
  
  Continuity And Compactness - 1 problems
  
  Continuous Functions (General Properties) - 4 problems
  
  Functions. Continuity (Other) - 5 problems
  
  Intermediate Value Theorem. Connectedness. - 2 problems
  
  Monotonicity, Boundedness - 8 problems
  
  Periodicity And Aperiodicity - 9 problems
  
  Functions Of Several Variables - 4 problems
  
  Integral - 3 problems
  
  Applications Of Integration - 1 problems
  
  Area By Integration - 1 problems
  
  Calculating Integrals - 1 problems
  
  Existence Of A Definite Integral - 1 problems
  
  Number Sequences - 31 problems
  
  Boundedness, Monotonicity - 6 problems
  
  Limit Of A Sequence, Convergence - 12 problems
  
  Number E - 2 problems
  
  Number Sequences (Other) - 11 problems
  
  Real Numbers - 117 problems
  
  Countable And Uncountable Subsets - 2 problems
  
  Integer And Fractional Parts. Archimedean Property - 86 problems
  
  Rational And Irrational Numbers - 28 problems
- Combinatorics - 23 problems
- Constructions - 8 problems
  Dissections - 2 problems
  
  Geometry - 3 problems
  
  Mathematical Logic - 1 problems
- Cryptography - 9 problems
  Number Theory - 9 problems
- Cube Nets - 1 problems
- Discrete Mathematics - 936 problems
  Algorithm Theory - 233 problems
  
  Balance Puzzles - 19 problems
  
  Cooperative Algorithms - 2 problems
  
  Game Theory - 109 problems
  
  Fun Games - 6 problems
  
  Game Theory (Other) - 34 problems
  
  Symmetric Strategies - 22 problems
  
  Winning And Loosing Positions - 39 problems
  
  Game Theory - 1 problems
  
  Theory Of Algorithms (Other) - 92 problems
  
  Combinatorics - 323 problems
  
  Colorings Of The Board - 18 problems
  
  Discrete Geometry (Other) - 2 problems
  
  Dissections, Partitions, Covers And Tilings - 63 problems
  
  Covers - 17 problems
  
  Dissections With Certain Properties - 8 problems
  
  Features Of Dissection Pieces - 3 problems
  
  Paritions Of Figures In Segments - 2 problems
  
  Tilings With Ordinary And Domino Tiles - 22 problems
  
  Various Dissection Problems - 6 problems
  
  Geometry On Grid Paper - 19 problems
  
  Integer Lattices - 14 problems
  
  Integer Lattices (Other) - 12 problems
  
  Polygons And Polyhedra With Vertices In Lattice Points - 2 problems
  
  Number Theory - 1 problems
  
  Packing Problems - 2 problems
  
  Painting Problems - 33 problems
  
  Permutations - 36 problems
  
  Systems Of Points And Line Segments - 10 problems
  
  Center Of Mass - 1 problems
  
  Center Of Mass Formula - 1 problems
  
  Systems Of Points - 1 problems
  
  Systems Of Points And Line Segments (Counterexamples) - 1 problems
  
  Systems Of Points And Line Segments (Other) - 3 problems
  
  Systems Of Points, Lines, And Line Segments - 3 problems
  
  Covers And Tilings - 2 problems
  
  Covers - 1 problems
  
  Game Theory - 1 problems
  
  Game Theory - 6 problems
  
  Graph Theory - 17 problems
  
  Lights Out - 15 problems
  
  Mathematical Logic - 3 problems
  
  Set Theory And Logic - 344 problems
  
  Linguistics - 2 problems
  
  Logic And Set Theory - 33 problems
  
  Mathematical Logic - 260 problems
  
  Mathematical Logic (Other) - 137 problems
  
  Paradoxes - 14 problems
  
  Puzzles - 56 problems
  
  Weightings - 1 problems
  
  Order Relations - 10 problems
  
  Set Theory - 34 problems
  
  Inclusion-Exclusion Principle - 6 problems
  
  Set Cardinality. One-To-One Correspondence - 1 problems
  
  Set Theory (Other) - 2 problems
  
  Union, Intersection, And Set Difference - 4 problems
  
  Unusual Constructions - 2 problems
- Dissections - 18 problems
  Joke Problems - 1 problems
  
  Puzzles - 1 problems
  
  Pythagorean Theorem - 1 problems
- Divisibility - 4 problems
- Fun Problems - 191 problems
  Arithmetic Puzzles - 6 problems
  
  Covers - 1 problems
  
  Dissections - 20 problems
  
  Dissections With Certain Properties - 1 problems
  
  Joke Problems - 33 problems
  
  Linguistics - 1 problems
  
  Tilings - 1 problems
  
  Word Problems - 113 problems
  
  Combined Labour (Work) Problems - 1 problems
  
  Motion Problems - 7 problems
  
  Percentages And Ratios - 8 problems
  
  Solving Problems By Inequalities. Going Through The Cases. - 5 problems
  
  Tables And Tournaments - 80 problems
  
  Chessboards And Chess Pieces - 34 problems
  
  Number Tables And Its Properties - 13 problems
  
  Tables And Tournaments (Other) - 22 problems
  
  Tournament Tables - 11 problems
  
  Tournament Tables - 1 problems
- Game Of Life - 12 problems
- Game Of Life - 1 problems
- Geometry - 528 problems
  Areas - 49 problems
  
  Combinatorial Geometry - 1 problems
  
  Constructions - 1 problems
  
  Dissections - 2 problems
  
  Euclidean Geometry - 2 problems
  
  Geometric Inequalities - 4 problems
  
  Triangle Inequality - 4 problems
  
  Geometry (Other) - 3 problems
  
  Plane Geometry - 253 problems
  
  Area - 44 problems
  
  Area Of A Circle, Sector, Segment - 9 problems
  
  Area Of A Parallelogram - 3 problems
  
  Area Of A Polygon - 2 problems
  
  Area Of A Trapezium - 2 problems
  
  Area Of Curvilinear Shapes - 1 problems
  
  Area Of Quadrilateral - 2 problems
  
  Area (Other) - 7 problems
  
  Area Ratio - 8 problems
  
  Area Ratio Of Similar Figures - 1 problems
  
  Area Ratio Of Triangles With Common Base And Height - 1 problems
  
  Area Ratio (Other) - 4 problems
  
  Finding The Area By Rearrangment - 5 problems
  
  Triangle Area - 5 problems
  
  Circles - 42 problems
  
  Central Angle. Arc Length And Circumference - 4 problems
  
  Circle, Sector, Segment, Etc - 1 problems
  
  Circles (Other) - 4 problems
  
  Connection Between The Arc Length, The Angle, And The Chord - 4 problems
  
  Diameter, Chords, And Secants - 2 problems
  
  Chords And Secants (Other) - 2 problems
  
  Four Points On A Circle - 2 problems
  
  Inscribed Angle - 10 problems
  
  An Angle Between A Secant And A Chord - 1 problems
  
  An Angle Between Two Chords Or Two Secants - 3 problems
  
  Angles Supported By Congruent Arcs And Chords - 4 problems
  
  Inscribed Angle (Other) - 2 problems
  
  Tangent Lines And Tangent Circles - 4 problems
  
  Tangent Circles - 2 problems
  
  Tangent Lines To Circles - 2 problems
  
  Constructions - 13 problems
  
  Apollonian Circles - 1 problems
  
  Circles (Construction) - 1 problems
  
  Construction Of A Triangle Given Different Points - 2 problems
  
  Constructions (Other) - 6 problems
  
  Similar Triangles And Homothetic Transformations (Construction) - 1 problems
  
  Unusual Constructions - 1 problems
  
  Constructing With Right Angle - 1 problems
  
  Convex And Non-Convex Figures - 4 problems
  
  Convex Polygons - 4 problems
  
  Dissections - 1 problems
  
  Geometrical Inequalities - 34 problems
  
  Area Inequalities - 2 problems
  
  Geometric Inequalities (Other) - 4 problems
  
  Inequalities In A Triangle - 10 problems
  
  A Perpendicular Distance Is The Shortest. Inequalities For Right Triangles - 1 problems
  
  A Segment Inside The Triangle Is Smaller Than The Largest Side ,Problems - 5 problems
  
  Geometry - 2 problems
  
  Plane Geometry - 2 problems
  
  Polygons - 1 problems
  
  Hexagons - 1 problems
  
  Triangles - 1 problems
  
  Types Of Triangles - 1 problems
  
  Right-Angled Triangles - 1 problems
  
  Pythagorean Theorem And Its Converse - 1 problems
  
  Methods - 2 problems
  
  Pigeonhole Principle - 2 problems
  
  Pigeonhole Principle (Angles And Lengths) - 1 problems
  
  Pigeonhole Principle (Finite Number Of Poits, Lines Etc.) - 1 problems
  
  Probability And Statistics - 1 problems
  
  Probability Theory - 1 problems
  
  Discrete Distribution - 1 problems
  
  Inequalities In A Triangle Involving Heights - 1 problems
  
  Inequalities In A Triangle Involving Medians - 1 problems
  
  The Longest Side Of The Triangle Lies Opposite The Largest Angle - 2 problems
  
  Polygons (Inequalities) - 2 problems
  
  Quadrilaterals (Inequalities) - 4 problems
  
  Triangle Inequality - 11 problems
  
  Triangle Inequality Algebra Problems - 3 problems
  
  Triangle Inequality (Other) - 4 problems
  
  Lines, Segments, Rays, And Angles - 6 problems
  
  Measurement Of Segments And Angles. Adjacent Angles. - 3 problems
  
  Locus - 9 problems
  
  Line Or Line Segment As A Locus - 1 problems
  
  Loci With Nonzero Area - 1 problems
  
  Locus And Auxiliary Triangles - 2 problems
  
  Locus (Other) - 4 problems
  
  Plane Transformations - 16 problems
  
  Isometry Of The Plane - 3 problems
  
  Rotations - 3 problems
  
  Parallel Translation - 4 problems
  
  Projection Onto A Line - 1 problems
  
  Orthogonal Projection - 1 problems
  
  Similarity - 7 problems
  
  Homothetic Transformations, Rotations Of Homothetic Transformations - 7 problems
  
  Polygons - 17 problems
  
  Inscribed And Circumscribed Polygons - 1 problems
  
  Pentagons - 1 problems
  
  Polygons (Other) - 6 problems
  
  Regular Polygons - 8 problems
  
  Sum Of Internal And External Angles Of Polygons - 1 problems
  
  Quadrilateral - 14 problems
  
  Arbitrary Quadrilaterals - 1 problems
  
  Circumscribed Quadrilaterals - 1 problems
  
  Inscribed Quadrilaterals - 1 problems
  
  Parallelogram - 9 problems
  
  Special Cases - 8 problems
  
  Rectangles And Squares. Criteria And Properties - 8 problems
  
  Trapeziums - 1 problems
  
  Triangles - 54 problems
  
  Incircle And Circumcircle Of A Triangle - 1 problems
  
  Relationship Of Side Lengths And Angles Of A Triangle. Solving Triangles. - 6 problems
  
  Ceva'S Theorem And Menelaus'S Theorem - 1 problems
  
  Law Of Sines - 3 problems
  
  Relations Between Sides And Angles Of A Triangle (Other) - 2 problems
  
  Remarkable Points And Lines In A Triangle - 1 problems
  
  Similar Triangles - 18 problems
  
  Auxiliary Similar Triangles - 1 problems
  
  The Triangle Generated By Bases Of Two Altitudes And A Vertex - 2 problems
  
  Sum Of Angles Of A Triangle. Exterior Angle Theorem - 2 problems
  
  Types Of Triangles - 20 problems
  
  Equilateral Triangle - 4 problems
  
  Right-Angled Triangles - 16 problems
  
  Pythagorean Theorem And Its Converse - 16 problems
  
  Vectors - 4 problems
  
  Law Of Polygon Of Vectors - 1 problems
  
  The Sum And The Difference Of Vectors, The Multiplication Of A Vector By A Scalar. Properties - 2 problems
  
  Visual Geometry - 5 problems
  
  Regular Polygons - 2 problems
  
  Shortest Paths - 10 problems
  
  Solid Geometry - 85 problems
  
  Convex Solids - 1 problems
  
  Lines And Planes In Space - 3 problems
  
  Parallelepipeds - 5 problems
  
  Special Cases Of Parallelepipeds - 5 problems
  
  Cube - 5 problems
  
  Polyhedra And Polygons In Space - 1 problems
  
  Regular Polyhedra - 1 problems
  
  Main Features And Definitions Of Regular Polyhedra - 1 problems
  
  Skeletons Of Multifaceted Figures - 3 problems
  
  Space Transformations - 10 problems
  
  Isometry - 7 problems
  
  Isometry Helps Solve The Problem - 1 problems
  
  Point Symmetry - 4 problems
  
  Reflectional Symmetry - 5 problems
  
  Projection - 2 problems
  
  Parallel Projection - 1 problems
  
  Orthographic Projection - 1 problems
  
  Area And Orthographic Projection - 1 problems
  
  Projection Helps Solve The Problem - 1 problems
  
  Similarity - 1 problems
  
  Spheres - 2 problems
  
  Circle On A Sphere - 2 problems
  
  Tetrahedron And Pyramid - 2 problems
  
  Particular Cases Of Tetrahedra - 1 problems
  
  Regular Tetrahedron - 1 problems
  
  Pyramid - 1 problems
  
  Square Pyramid - 1 problems
  
  Visual Geometry In Space - 55 problems
  
  Volume - 8 problems
  
  Ratio Of Volumes - 2 problems
  
  Volume Of A Parallelepiped - 1 problems
  
  Volume Of A Prism - 1 problems
  
  Volume Of A Tetrahedron And Pyramid - 1 problems
  
  Symmetry - 21 problems
  
  Triangle Inequality - 9 problems
  
  Triangles - 3 problems
  
  Visual Geometry In Space - 1 problems
- Graph Theory - 43 problems
- Graph Theory - 9 problems
- Inequalities - 12 problems
- Invariants - 10 problems
- Lights Out - 3 problems
- Locus - 1 problems
- Logic - 2 problems
- Mathematical Logic - 99 problems
  Invariants - 18 problems
  
  Liars And Knights - 1 problems
  
  Liars And Knights - 1 problems
  
  Logic And Set Theory - 1 problems
  
  Weightings - 1 problems
- Methods - 649 problems
  Algebraic Methods - 78 problems
  
  Counting In Two Ways - 21 problems
  
  Iterations - 5 problems
  
  Partitions Into Pairs And Groups; Bijections - 22 problems
  
  Processes And Operations - 12 problems
  
  Proof By Exhaustion - 20 problems
  
  Symmetry And Involutions - 2 problems
  
  Working Backwards - 1 problems
  
  Colouring - 32 problems
  
  Chessboard Colouring - 10 problems
  
  Colouring (Other) - 7 problems
  
  Examples And Counterexamples - 3 problems
  
  Examples And Counterexamples. Constructive Proofs - 68 problems
  
  Extremal Principle - 18 problems
  
  Extremal Principle (Other) - 12 problems
  
  Smallest Or Largest Distance (Length) - 1 problems
  
  Sorting In Increasing (Decreasing) Order - 4 problems
  
  Invariants And Semi-Invariants - 38 problems
  
  Invariants - 26 problems
  
  Mathematical Induction - 59 problems
  
  Mathematical Induction In Geometry - 3 problems
  
  Mathematical Induction (Other) - 11 problems
  
  Methods For Solving Problems With Parameter - 1 problems
  
  Methods From Geometry - 2 problems
  
  Geometric Interpretations In Algebra - 2 problems
  
  Methods Of Calculus - 3 problems
  
  Continuity Considerations - 2 problems
  
  Monotonicity And Boundedness - 1 problems
  
  Pigeonhole Principle - 408 problems
  
  Pigeonhole Principle (Angles And Lengths) - 61 problems
  
  Pigeonhole Principle (Area And Volume) - 13 problems
  
  Pigeonhole Principle (Finite Number Of Poits, Lines Etc.) - 49 problems
  
  Pigeonhole Principle (Other) - 247 problems
  
  Proof By Contradiction - 64 problems
  
  Trial And Error - 2 problems
- Number Theory - 32 problems
  Numeral Systems - 13 problems
- Number Theory - 425 problems
  Arithmetic - 1 problems
  
  Arithmetic Operations. Number Identities - 59 problems
  
  Divisibility - 284 problems
  
  Arithmetic Functions - 4 problems
  
  Divisibility Of A Number. General Properties - 52 problems
  
  Divisibility Rules - 42 problems
  
  Divisibility - 1 problems
  
  Divisibility Tests For 2 And 4 - 3 problems
  
  Divisibility Tests For 3 And 9 - 16 problems
  
  Divisibility Tests (Other) - 1 problems
  
  Division With Remainders. Arithmetic Of Remainders - 62 problems
  
  Arithmetic Of Remainders - 12 problems
  
  Division With Remainder - 41 problems
  
  Euler'S Theorem - 4 problems
  
  Fermat'S Little Theorem - 1 problems
  
  Equations In Integer Numbers - 24 problems
  
  Odd And Even Numbers - 55 problems
  
  Prime Numbers - 5 problems
  
  Products And Factorials - 5 problems
  
  The Fundamental Theorm Of Arithmetic. Prime Factorisation. - 10 problems
  
  The Greatest Common Divisor (Gcd) And The Least Common Multiplier (Lcm). Mutually Prime Numbers - 18 problems
  
  Equations In Integer Numbers - 2 problems
  
  Number Systems - 1 problems
  
  Decimal Number System - 1 problems
  
  Number Theory. Divisibility - 1 problems
  
  Divisibility Rules - 1 problems
  
  Numeral Systems - 59 problems
  
  Binary Number System - 5 problems
  
  Decimal Number System - 52 problems
  
  Number Systems (Other) - 1 problems
- Number Theory. Divisibility - 1 problems
- Numeral Systems - 1 problems
- Pigeonhole Principle - 1 problems
- Pigeonhole Principle - 3 problems
- Polynomials - 1 problems
  Invariance Principle - 1 problems
- Probability And Statistics - 155 problems
  Probability Theory - 132 problems
  
  Conditional Probability - 21 problems
  
  Continuous Distribution - 12 problems
  
  Discrete Distribution - 100 problems
  
  Probability Theory (Other) - 14 problems
  
  Statistics - 10 problems
- Proof By Contradiction - 2 problems
- Proof By Contrapositive - 1 problems
- Puzzles - 2 problems
- Shortest Paths - 1 problems
- Topology - 25 problems
  Knots - 1 problems
  
  Torus - 1 problems
- Visual Geometry - 1 problems
- Visual Geometry In Space - 1 problems