If you ever doubted that math could be useful to you, this book will dispel your doubts.The beauty of the 10 equations given here is that they permeate all areas of life, whether it be smart rates, filtering meaningful information, accuracy predictions, degree of influence or effectiveness of advertising.If you learn to isolate data and mathematical models from what is happening, then you will begin to see relationships, as if on an x-ray. Moreover, you will be able to manage processes that seem chaotic to others.This is the meaning of applied mathematics.Published in Russian for the first time.