The first volume of seventh grade mathematics is a book published by People's Education Press 20 12. The author is the research and development center and research institute of middle school mathematics curriculum materials of People's Education Press.

The first volume of seventh grade mathematics, ISBN: 9787107244537 [1] [1]. This book is divided into four chapters, namely the first chapter, rational numbers. Chapter two, addition and subtraction of algebraic expressions. Chapter 3, One-dimensional linear equation. Chapter four, preliminary geometry. Note that these four chapters are all new versions adopted by 20 12.

On the number axis, the distance from the origin of a number is called the absolute value of the number.