It is well known that Physics uses Mathematics, how do they interact with Physics? A characteristic historical example is the "invention" of differ-ential and integral calculus by Newton, who used them in order to found and study the well-known law of gravitational attraction. On the other hand some Mathematical theories seem to be a game of logic without any application. A characteristic example is the group theory of Galois, a well-founded theory which seemed to have no practical application. In the course it became a valuable tool in the hands of Physicists, in the study of symmetries in nature. In this book we try to make known the necessity of the use of Mathematics in Physics and especially in General Physics, which is the first step of familiarization of the future scientist with the subject, but also with science in general. We taught for many years Physics in high school and in the first years of University, giving lectures to students of exact sciences and also theoret-ical Sciences. This experience made clear to us that a majority of pupils and students, no matter which is their level of mathematical knowledge, they have an important difficulty to familiarize themselves with the use of Mathematics in Physics. Most of them think that Mathematics is an addi-tional difficulty, while others, usually a few of them, try to work with eve-ry physics question only approaching it with Mathematic, and the forget that often the Physics reasoning approach is easier and sometimes the only correct one. The book comprises 12 chapters, each of which has the following structure: First we try to introduce the corresponding Mathematical notion from the point of view of Physics, substantiating its necessity on the basis of some Physical problems. Then we present this Mathematical notion and we give basic rela-tions, properties and theorems without proof. At this part, for a better assimilation of the corresponding material a number of examples is in-cluded. They are those that their numeration begins with the letter M. Then, whenever this is possible, a set of basic Physics formulas is given, where the corresponding Mathematical notion is involved. All the above is followed by examples from Physics which involve the use of the corresponding Mathematics. All of these examples have a numeration which begins with the letters PH. Each chapter ends with some unsolved exercises, which involve the corresponding Mathematics. We believe that the structure of this book make it useful for the two final years of High School, for their teachers, but also for University students of the exact sciences of the first two years, perhaps also beyond the second year.