Book excerpt: Discover modern solutions to ancient mathematical problems with this engaging guide, written by a mathematics enthusiast originally from South Vietnam. Author Dat Phung To provides a theory that defines the partial permutations as the compositions of the permutations nPn=n!. To help you apply it, he looks back at the ancient mathematicians who solved challenging problems. Unlike people today, the scholars who lived in the ancient world didn?t have calculators and computers to help answer complicated questions. Even so, they still achieved great works, and their methods continue to hold relevance. In this textbook, you?ll find fourteen ancient problems along with their solutions. The problems are arranged from easiest to toughest, so you can focus on building your knowledge as you progress through the text. Fourteen Ancient Problems also explores partial permutations theory, a mathematical discovery that has many applications. It provides a specific and unique method to write down the whole expansion of nPn = n! into single permutations with n being a finite number. Take a thrilling journey throughout the ancient world, discover an important theory, and build upon your knowledge of mathematics with Fourteen Ancient Problems.