Throughout all these years, I have designed novel ways of learning mathematics. I am convinced that if someone is not madly in love with mathematics it is because he or she has not been properly introduced to this marvelous subject. My work has shown me that students themselves can discover and invent the solutions to any mathematical problem and that they do not need someone to explain a method or give them a set of instructions to solve it. It is only necessary to ask the right questions, and the students will always find the correct answers. Recently, I designed a series of activities for children so that they can discover algebra. I think that instead of presenting algebra as a collection of rules, children can "invent" themselves the algebraic representation. This book pretends to be a guide for children to create symbolic representations of daily-life questions. The exercises will also be the basis for learning how to write the correct formulas of chemical compounds. Yes, this book is also an introduction to the concept of electrons in the valence shell of a molecule . . . and it is for children! If you do not believe me, just read it.