Introduction
Structure of this book
Study in this order

| In-depth study by unit |
Unit 1: Range and Estimation of Numbers
Unit 2 Multiplication of Fractions
Unit 3 Congruence and Symmetry
Unit 4 Multiplication of Decimals
Unit 5 Rectangular Solid
Unit 6: Mean and Probability

| In-depth Comprehensive |
1 set
2 sets
3 sets
4 sets
5 sets

| Skills Diagnostic Test |

Why Choose "Open Advanced" as Your Child's First Advanced Textbook

Why do children who are just starting advanced classes fail? It's because they can't adapt to existing advanced materials.
There are too many unnecessary problems, too difficult, and too much material to develop deep learning skills.
This is why, no matter how much a mother tells her child that advanced study is important, the child shakes his head when he even looks at advanced study materials.

This book began with the question of how children can successfully complete advanced studies.
The purpose of deepening is to solve problems and develop problem-solving skills.
To do that, you first have to make it loose.
This workbook, created from the perspective of students who are new to advanced learning, is a new concept introductory textbook called “Open Advanced Learning.”

1.
Step-by-step hint-style answer sheets to help children solve problems on their own
This is the most important feature of this book.
The purpose of deepening is not to 'solve' the problem, but to solve the problem 'by yourself'.
Therefore, if you immediately look at the answer sheet and memorize the solution because you are having trouble solving it, it will have no effect at all in solving the advanced problems.
Therefore, the answers and solutions in this book are organized in a way that gives hints up to three levels before looking at the full solution.
The goal is to provide the experience of solving problems on your own, as much as possible, by providing only a few hints.
As you gain experience solving problems on your own, your problem-solving skills will improve.

2.
Problems carefully selected by Ryu Seung-jae, author of "Su-Jal-Gong"
It consists of only good problems worth investing time and effort into solving.
These are meaningful problems in terms of their connection to the secondary curriculum, and problems that are good to solve.
The preceding concepts only include those that are meaningful at this stage.
Also, since many children give up trying to tackle advanced textbooks that are too difficult compared to applied textbooks, the difficulty level was appropriately adjusted to ensure a smooth transition from applied to advanced textbooks while preserving the spirit of solving difficult problems on one's own.

3.
From concept confirmation to in-depth learning and skill verification, everything is covered.
This book first reviews the basic concepts learned in textbooks and concept/application textbooks by unit.
Then, solve important advanced problems to become familiar with them.
Next, you will solve an in-depth comprehensive exam in the form of a mock exam, and at the end, you will finish with a 'skill diagnostic test' to check your skills.
Therefore, if you solve this book, you will have the effect of summarizing one semester's worth of material, from the textbook to the advanced level. In addition, you will be able to check your objective skills and decide which workbook to solve next.
This is an in-depth problem book that opens the door to the vast world of mathematics.