Didactics

Multiplication tables

Poster and mug to learn the multiplication tables.

• Triangular multiplication tables poster (the multiplication by 1 is omitted, and there are no repetitions in the products).
• Triangular multiplication tables for a mug.
• Multiplication tables on a number stripe, poster.
• Multiplication tables and factorizations on a number stripe, poster for math-enthusiasts.

Geometry Posters

Poster with 96 images of geometry.

• Poster and Small posters in English.
• Poster and Small posters in German.
• Poster and Small posters in French.

The Chinese Remainder Clock

A mathematical clock based on the Chinese Remainder Theorem.

• The official webpage of the CR-Clock: there you find articles, animations, and you can download a free App with the clock!

Math around the Clock

Various original mathematical clocks.

• The article Maths Around the Clock in Plus Magazine.
• Various original mathematical clocks.

Visualizing recurrence sequences

A sliding mask to understand recurrence sequences.

• Unmasking recurrence sequences, Pi in the Sky (Issue 21, 2019).

Multisets in Arithmetic

About the multiset of prime factors.

• Multisets in Arithmetic, to appear in Plus Magazine.
• Discover multisets, pdf, basis for the article Multiverzamelingen, Uitwiskeling (vol. 35, no. 4).

Mathematical Induction

Illustrating the Principle of Mathematical Induction.

• with Milko Todorovic, the article Visualizations for the Principle of Mathematical Induction (here the Slides) about the variants of the Principle of Mathematical Induction and how to illustrate them.

Mathematical Quizzes

One Quiz about plane geometry.

• The Quiz (in German) Beat the Prof: Ebene Geometrie, published on Zeit Online on December 2, 2018. The Quiz is without time limit, and it is recommended for math teachers.

The Mastermind Wheel

A didactical tool for understanding Knuth's algorithm for winning Mastermind in at most five moves.

• The Master Mind Wheel and some introductory Slides.
• with Thomas M. Fiore and Alexander Lang, Tactile Tools for Teaching: Implementing Knuth's Algorithm for Mastering Mastermind, The College Mathematics Journal, Volume 49 (2018) Issue 4.

Sim!Cong!

A didactical card game for learning the Congruence and Similarity Theorems for triangles.

• Sim!Cong!, The instructions and the set of printable cards (free for personal use, or use in class for instructors).
• Leaflet, Guidelines for commercial use (University of Luxembourg).

5-Con triangles

Triangles that are almost congruent.

• The article 5-Con triangles.
• Creation of the Wikipedia page 5-Con triangles.

Arithmetic billiards

A geometric construction for the gcd and the lcm.

• The article Arithmetic billiards in Plus Magazine. An addition which is joint work with Bruno Carvalho da Veiga pdf.
• Creation of the Wikipedia page Arithmetic Billiards.

Mathematik zum Anfassen

Documentation about the mobile exhibition of the mathematikum.

• With the students of the Master of Secondary Education, the detailed description of the exhibition Mathematik zum Anfassen of the mathematikum. With Bruno Teheux, slides explaining some of the exhibits.

History of mathematics

The Babylonian tablet Plimpton 322.

• with Deborah Stranen, the article Understanding the Babylonian tablet 'Plimpton 322' with the decimal system (here the Slides).

"Understanding the Babylonian table 'Plimpton 322' with the decimal system makes an interesting contribution to the history of mathematics." (Reviewer)

Trigonometry

Sines and cosines expressed by radicals.

• with Deborah Stranen, the article Trigonometry for the multiples of 3 degrees.
• with Deborah Stranen, creation of the Wikipedia page Trigonometrische Konstante ausgedrückt in reellen Radikalen.

Mathematical riddles

The Hardest Logic Puzzle Ever.

• The article The Hardest Logic Puzzle Ever, to appear in Pi in the Sky.
• with Andreas Gramsamer, creation of the Wikipedia page Das Schwierigste Rätsel der Welt.

Mathematical riddles for everyone.

• with Jerry Hilgert, Riddelicious, mathematical riddles set in the Luxembourgish context, in English, German, French.

Further mathematical articles

Mockingjay Mathematics (movie-inspired problems).

• The exercise sheet Mockingjay Mathematics.

The Art Gallery Problem.

• The article The Art Gallery Problem.

The 15-puzzle.

• The article The 15-puzzle.

The 'Four points, two distances' problem.

• The article Four points, two distances.

The 7 bridges problem.

• The article The seven bridges of Königsberg.

Further mathematical exhibits

Drehoskop (to explore solids).

• With Edith Wittman, Drehoskop, a tool to detect rotational symmetries for polyhedra (these can rotate on various axes).

A mathematical exhibit around Pythagoras' Theorem.

• PytEuk, an exhibit that shows Pythagoras' Theorem and some related result by means of puzzles.

Placing the numbers 1,3, and 5.

• The 135 Exhibit, with two formulas related to the number 135, pdf.

GoFlex (composable flexible stripes).

• GoFlex, reconfigurable flexible stripes to create Möbius bands and other geometrical objects.