# Didactics

MATHEMATICS IS COLORFUL

## NEW: UNCONSCIOUS ASSUMPTIONS PROJECT

An ongoing collaborative didactical project about unconscious assumptions in examples for high-school mathematics. See the webpage of the project.

## POSTERS AND MUGS ### Easy Multiplication Tables

Posters and Mugs with the Easy Multiplication Tables. The multiplication by 1 is omitted, and there are no repetitions in the products (for example you have 6x8 but not 8x6). Some Explanations of the Easy Multiplication Tables. ### Geometry Posters

Poster with 96 images of geometry.

## CLOCKS ### The Chinese Remainder Clock

A mathematical clock based on the Chinese Remainder Theorem. ### Math around the Clock

Various original mathematical clocks.

## POPULARIZATION ARTICLES ### History of mathematics

The Babylonian tablet Plimpton 322: constructing a decimal analogue.
• with Deborah Stranen, the article Converting the Old Babylonian Tablet ‘Plimpton 322’ into the Decimal System as a Classroom Exercise, published in Convergence (here the Slides). ### Visualizing recurrence sequences

A sliding mask to understand recurrence sequences.
• Unmasking recurrence sequences, Pi in the Sky (Issue 21, 2019). ### Arithmetic billiards

A geometric construction for the gcd and the lcm. ### Master Mind

The Mastermind Wheel (A didactical tool for understanding Knuth's algorithm for winning Mastermind). ### Logic Puzzles

The hardest logic puzzle ever.

## ARTICLES FOR UITWISKELING   Sines and cosines expressed by radicals.
• with Deborah Stranen, the article Trigonometry for the multiples of 3 degrees.
5-Con triangles (Triangles that are almost congruent).
The Art Gallery Problem.
• The article The Art Gallery Problem.
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.
Multisets.
• with Engjëll Begalla, the article The ABCD of cyclic quadrilaterals.

## FURTHER EXHIBITS  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.
• Leaflet, Guidelines for commercial use (University of Luxembourg).
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.

## MISCELLANEA   A webpage explaining how to solve the Rubik's Cube.
• With Daniel Zuk and Sebastiano Tronto, the webpage in English, German, and French.
Mathematical riddles for everyone.
• with Jerry Hilgert, Riddelicious, mathematical riddles set in the Luxembourgish context, in English, German, French.
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.
Proof without words (Mathematical images explaining proofs).
• with Pietro Sgobba and Sebastiano Tronto, colorful images for the series Proof without words.