Getting started...

Given the below relation, in the set use your keyboard to play the piano, following the exact order.

Click the button to enable keyboard input. To start over, hit space.

Let's practise on relations

This tool provides to the students, of the Discrete Structures course, a number of selected material and problems to help them to learn and practise the required concepts of Mathematical Relations, namely:

Binary relations

Students will learn how to relate elements between sets and express relations as sets of ordered pairs.


Students will learn to express relations as matrices.


Students will express relations as graphs.

Properties of relations

Students will to classify relations by their properties such as transitive, symmetric, reflexive and anti-symmetric.


This tool was developed for you to effectively help you to understand the material. Remember that failure should neither be considered inevitable or irrevocable but an attempt to learn. Try to solve as many exercises as you can to collect the most points in the class! On the final step, you will be tested on what you have learned. Prove to your instructor that mathematical relations can be an easy game as long as you take advantage of PLR.


The darker the background, the more the difficulty level.

White buttons count, think before checking your answer, otherwise you will receive a bronze badge in your collection.