# Geometry for Elementary School/Introduction

## Why geometry?

editGeometry is one of the most elegant fields in mathematics. It deals with visual shapes that we know from everyday life.

## Who should use this book?

editThis book is intended for use by a parent (or a teacher or ward) and a child. It is recommended that the parent have some familiarity with geometry, but this is not necessary. The parent can simply read the chapter before teaching the child and then learn it together.

## Book guidelines

editThe classic book about geometry is Euclid's *Elements*. This book helped teach geometry for hundreds of years, so we feel that writing this book based on the Elements is a correct step.

We will adapt parts of the book for children and modify the order of some topics in order to make the book clearer.

The learning will be based on constructions and proofs. A construction is a method of creating a geometric object (such as a triangle) using a set of tools. In the case of this book, the tools we will be using are a compass and a ruler. A proof is a logical trail where we can prove one fact by starting with some given information and make a series of conclusions based on that information. Oftentimes it is more difficult to prove a result than to simply find the result.

The constructions are useful for letting the child experience geometric ideas and get visual results.

The proofs are a good way to understand geometry and are a good basis for future study of logic.

Since the book is for children, we omit some of the proof details and use intuition instead of precise definition. On the other hand, we insist on correct and elegant proofs. Precise definitions and exact proofs can be found in regular geometry books and can be used to extend to material to some of the children.

## Notation

editThe notation that is used in the book is defined the first time it is used. However, in order to simplify its use, it is also summarized in the *notation* section of the *conventions* chapter at the end of the book.

## How to contribute to this book

editThis book uses British English as a primary language; however, there is a table provided at the end of this book that summarises all the American terms that readers may come across.

## Before using this book

editMake sure that these resources are available before using this book:

- A protractor
- A compass
- A ruler
- Graph paper
- Single-lined paper