Author's Note
Introduction

Part 1: The Story of Mathematics in History Through the Eyes of the People
1.
Sejong also learned mathematics
_Sejong's love of mathematics
2.
A showdown with Chinese mathematicians
_Survival math game with Qing envoy Ha Guk-ju
3.
Are you glad you failed the exam in the past?
_Hong Dae-yong, a true Joseon nobleman
4.
Hague envoy, Lee Sang-seol
The Life of Lee Sang-seol, an Independence Activist Who Studied Mathematics
5.
Has anyone ever fought for independence through mathematics?
_Struggle to save the country with mathematics

Part 2 _Our Endless Old Mathematics
1.
If you go to Gyeongju, you will see Silla mathematics.
Mathematics of the Three Kingdoms Period
2.
Magic Square, its mysterious name
_Our Magic Square Story
3.
Oh, that's right, our math is
_The foundation of industry-academia cooperation
4.
Could old math problems appear on college entrance exams today?
How to Enjoy Old Math Problems
5.
Famous scenes from Joseon mathematics
_24 scenes through a folding screen
6.
Joseon Dynasty Mathematics Theorem
_The environment of Joseon's industrial and academic circles and the scholars of the yangban class

Outgoing remarks
References

An exciting journey to discover the roots of our mathematics.
Adding 'history' to 'our math' and removing 'prejudice'!

The Math Stories of Our Ancestors, Told by Professor Lee Jang-ju

Mathematics is a very important subject in schools today, but many students still have the prejudice that it is a difficult subject.
Rather, it is easy to envy our ancestors, thinking that they only studied Chinese characters by memorizing the Thousand Character Classic instead of the troublesome math.
It is true that the history of mathematics in our country has not been properly evaluated despite its greatness.
In fact, our ancestors were more interested in mathematics than anyone else, studied hard, and achieved outstanding results.
This book was published with the hope that students growing up would properly understand the history of our mathematics and take pride in it, by collecting the mathematical stories of our ancestors into one volume.
We have been able to achieve our current development based on the academic knowledge we inherited from our ancestors.
We also have the task of further efforts to uncover the mathematical legacy of our ancestors that remains hidden.


Let's go meet the people who made our math shine!

The author of this book, Professor Lee Jang-ju, teaches high school students and is diligently studying to find the roots of our mathematics at the Korean Society for the History of Mathematics.
This book was compiled with a passion and pride in mathematics, as well as love for students and a heart that cares for future mathematics teachers.


This book has tried to describe in detail the development of mathematics in our past, the outstanding scholars, and the stories surrounding them.
I added and decorated it little by little based on the material to arouse interest.
Through this book, readers will be able to encounter the great mathematical spirit of our ancestors and acquire a wealth of mathematical knowledge.


First, Part 1 focuses on introducing people related to our old academia.
First, let me introduce an anecdote about King Sejong, a great king of Joseon who studied mathematics diligently.
He also meets Hong Jeong-ha and Yu Su-seok, the great mathematicians of Joseon who had a mathematical competition on equal footing with Ha Guk-ju, a Chinese envoy who came to Joseon during the reign of King Sukjong.
Next, we introduce Damheon Hong Daeyong, an outstanding scholar and Silhak scholar of Joseon.
Hong Dae-yong was a theologian who traveled to and from the Qing Dynasty and acquired the most advanced scientific technology of his time.
Next, we introduce two representative independence activists who made desperate efforts to save the country during the late Joseon Dynasty, a time of rapid change when new civilizations emerged and foreign invasions began.
These people had a sense of mission that the advancement of mathematics was absolutely necessary to develop the nation's strength.
We meet Mr. Lee Sang-seol, who studied mathematics diligently and wrote mathematics books while suffering the pain of losing his country, and we also introduce materials related to Mr. Nam Sun-hee, who attempted modern education to save the country through mathematics.

Our old mathematics through examples and pictures

Part 2 then explains various interesting things related to industry-academia itself in a fun way that will inspire mathematical inspiration.
First, we will take a time machine and fly to Gyeongju, the capital of Silla, and encounter ancient mathematical relics such as Cheomseongdae and Seokguram Grotto.
A brief look at these outstanding artifacts will give us an idea of ​​how advanced the mathematics was at the time.
Next, we meet Choi Seok-jeong, a Joseon mathematician who is recognized for his outstanding research while standing shoulder to shoulder with world-class mathematicians.
Choi Seok-jeong wrote the mathematics book 『Gusuryak』 and is famous for his research on magic squares.
After meeting Choi Seok-jeong, we fly to the math test center and look at the outstanding mathematical algorithms studied by our ancestors, such as Sangajji, Cheonwonsul, and Yeongbujoksul.


And by solving various examples of ancient mathematics that are still used or appear on today's math tests, we vividly experience the mathematics of our ancestors.
Next, we will see a wonderful folding screen.
To summarize the true value of Joseon's academia, we will select 24 famous scenes with the greatest mathematical significance and display them on a folding screen that we created ourselves.
Finally, we will conclude the book by examining the environment of Joseon's industrial and academic circles and the outstanding scholars of the yangban class.


Did King Sejong also receive difficult math tutoring?
Revisiting our math

If you ask who the greatest person of the Joseon Dynasty is, many people will think of Admiral Yi Sun-sin and King Sejong.
Admiral Yi Sun-sin, who played a key role in leading the Japanese invasions of Korea to victory, created the turtle ship and protected the country from foreign invasion.
Hangul, created by King Sejong and the scholars of Jiphyeonjeon, is a scientific writing system that combines consonants and vowels and adds final consonants to create an enormous number of 'cases'.
Sejong's amazing wisdom is hidden right here.
Just like this, ‘mathematics’ is hidden beneath these dazzling developments.
Sejong took time out of his day to learn mathematics from Jeong In-ji, a third-rank official at Jiphyeonjeon.
Sejong knew well that mathematics was an important discipline that served as the foundation for governing the country, and he studied it diligently.
Thanks to this, I was able to achieve great achievements that are respected to this day.

In this way, mathematics has held a firm position as the most important basic discipline from ancient times to the present.
This is precisely why we need to break away from the prejudice that mathematics is difficult and boring and look at it again with affection and interest.
Through this book, you will rediscover your interest in mathematics by encountering the mathematics developed by our ancestors, and furthermore, you will be able to feel pride in your own mathematics.