10 is not bigger than 9

Author: Zheng Jiayong
Publisher:
Publish Date: 2006-06-01
Features:
★ Selected as the theme book for "TV Storytelling" by KBS, the largest and most representative broadcasting station in South Korea.
★ A topic book serialized for 5 consecutive years in South Korea's Dong-a Ilbo.
★ A book that inspired dedicated columns and heated discussions across several South Korean media outlets.
★ In 2005, the phrase "Do you know the book Ten is Not Greater Than Nine? Do you know its author?" became a common greeting in South Korea.
★ Breaking down universal economic concepts. "When we choose to do one thing, we must give up doing another simultaneously," the true story of how opportunity cost can change a person's fate.
Professor Zheng Jiayong of Yonsei University's Economics Department explores this in his book, using engaging language to explain complex economic terms through famous works such as plays, poems, novels, and films, as well as everyday aspects of life like love, marriage, family, and shopping. It conveys an obvious truth: economic activities are everywhere in our daily lives. Economics and markets exist in coffee seeds, guinea pigs, and other plants and animals; they exist in Figaro and The Knight of the Rose; they exist in human love and marriage. Economic activities are happening all around us.
Since its publication in South Korea in 2001, Ten is Not Greater Than Nine has resonated deeply with readers and gained widespread acclaim. It quickly spread across diverse audiences, being reprinted 15 times in a short period and revised for multiple editions, consistently ranking among the bestsellers. Zheng Jiayong has become a symbol, a banner—his books are deeply rooted in the daily lives of ordinary people, exploring and explaining economic principles within ordinary contexts. Through simple and accessible language, readers gain insights into the connection between life and economics, learning to think and view life from an economic perspective.
Have you ever been puzzled by the title Ten is Not Greater Than Nine? Even elementary school students know that 9 is less than 10, and 10 is greater than 9. Yet the author claims that "ten is not greater than nine." Mathematically, 10 is indeed greater than 9, but life in this world isn’t just about cold calculations like addition, subtraction, multiplication, and division; it’s also about rich emotions. Take a simple example: women all wish to stay forever at 29, who would want to become a 30-year-old woman? Though it defies mathematical logic, deep down, we still feel that 9 is more precious than 10.
The same principle applies to business production—achieving equilibrium quantity maximizes profit. That’s why shrewd manufacturers don’t expand production endlessly. They understand that producing 9 goods rather than 10 can better guarantee profit.
Throughout the book, there are many more examples exploring economic principles in everyday life, all conveying an obvious truth: economic activities are everywhere in our daily lives. Economics and markets exist in coffee seeds, guinea pigs, and other plants and animals; they exist in Figaro and The Knight of the Rose; they exist in human love and marriage. Economic activities are happening all around us.