A Robert does not like mathematics, as happens to many people, because just not understand. But one night he dreams of a little devil that seeks to initiate him into the science of numbers. Naturally, Robert thinks it is another of his frequent nightmares, but actually is the beginning of a new and exciting journey through the world of mathematics. Is not it strange always find numerical sequences by simple multiplication of about 1 x 1 = 1, 11 x 11 = 121, 111111 x 111111 = 12345654321, and so on? And this is just the simplest operation. For twelve nights, Robert dreams of increasingly unbelievable number systems. Suddenly, the numbers come alive for themselves, a mysterious life that even the devil can fully explain. Math had never been so fascinating. Soon, the devil will leave school topics and make access to higher levels: and still understands! And the young reader too. The numbers, each page that happens, they are becoming increasingly absorbent. It's like magic, and Robert wants to know more and more until, finally, the devil makes you realize that some problems and paradoxes belong to the upper echelons of science.