This teaching and learning module offers simple algebra as well as very understandable infinitesimal mathematical derivations. This leads to a level of knowledge that enables the determination of the centroids of all conceivable, representatively composed areas. The step-by-step solutions to examples and exercises are presented using the summation formula and clear tables. Many notes on the mathematical derivation, along with didactically prepared graphics, provide lasting support for the learner. As a result, an additional exercise or practice book becomes unnecessary.