Unequal: The Math of When Things Do and Don't Add Up
Why the familiar equal sign isn't just a marker of sameness but a gateway into math's-and humanity's-most profound questions

Math is famous for its equations: 1 + 1 = 2, a2 + b2 = c2, or y = mx + b. Much of the time it can seem like that's all mathematics is: following steps to show that what's on one side of an equation is the same as what's on the other.

In Unequal, Eugenia Cheng shows that's just part of the story, and the boring part to boot. Mathematics isn't about showing how numbers and symbols are the same. It isn't even just about numbers and symbols at all, but a world of shapes, symmetries, logical ideas, and more. And in that world, the boundary between things being equal and unequal is a gray area, or perhaps a rainbow of beautiful, vibrant, subtly nuanced color.

As Unequal shows, once you go over that rainbow, almost everything can be considered equal and unequal at the same time, whether it's shapes (seen from the right perspective, a circle is the same as an ellipse), words (synonyms), or people-even numbers! It all depends on what features we care about. And it's up to us what we do about it. That's because mathematics isn't a series of rules, facts, or answers. It's an invitation to a more powerful way of thinking.
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Unequal: The Math of When Things Do and Don't Add Up
Why the familiar equal sign isn't just a marker of sameness but a gateway into math's-and humanity's-most profound questions

Math is famous for its equations: 1 + 1 = 2, a2 + b2 = c2, or y = mx + b. Much of the time it can seem like that's all mathematics is: following steps to show that what's on one side of an equation is the same as what's on the other.

In Unequal, Eugenia Cheng shows that's just part of the story, and the boring part to boot. Mathematics isn't about showing how numbers and symbols are the same. It isn't even just about numbers and symbols at all, but a world of shapes, symmetries, logical ideas, and more. And in that world, the boundary between things being equal and unequal is a gray area, or perhaps a rainbow of beautiful, vibrant, subtly nuanced color.

As Unequal shows, once you go over that rainbow, almost everything can be considered equal and unequal at the same time, whether it's shapes (seen from the right perspective, a circle is the same as an ellipse), words (synonyms), or people-even numbers! It all depends on what features we care about. And it's up to us what we do about it. That's because mathematics isn't a series of rules, facts, or answers. It's an invitation to a more powerful way of thinking.
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Unequal: The Math of When Things Do and Don't Add Up

Unequal: The Math of When Things Do and Don't Add Up

by Eugenia Cheng

Narrated by Eugenia Cheng

Unabridged — 12 hours, 56 minutes

Unequal: The Math of When Things Do and Don't Add Up

Unequal: The Math of When Things Do and Don't Add Up

by Eugenia Cheng

Narrated by Eugenia Cheng

Unabridged — 12 hours, 56 minutes

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Overview

Why the familiar equal sign isn't just a marker of sameness but a gateway into math's-and humanity's-most profound questions

Math is famous for its equations: 1 + 1 = 2, a2 + b2 = c2, or y = mx + b. Much of the time it can seem like that's all mathematics is: following steps to show that what's on one side of an equation is the same as what's on the other.

In Unequal, Eugenia Cheng shows that's just part of the story, and the boring part to boot. Mathematics isn't about showing how numbers and symbols are the same. It isn't even just about numbers and symbols at all, but a world of shapes, symmetries, logical ideas, and more. And in that world, the boundary between things being equal and unequal is a gray area, or perhaps a rainbow of beautiful, vibrant, subtly nuanced color.

As Unequal shows, once you go over that rainbow, almost everything can be considered equal and unequal at the same time, whether it's shapes (seen from the right perspective, a circle is the same as an ellipse), words (synonyms), or people-even numbers! It all depends on what features we care about. And it's up to us what we do about it. That's because mathematics isn't a series of rules, facts, or answers. It's an invitation to a more powerful way of thinking.

Editorial Reviews

From the Publisher

Cheng’s aim is to explore how we decide when things are “the same” in mathematics. Her approach is both playful and deeply serious, leavening abstract concepts with entertaining tangents on everything from knitting Möbius strips to making an iterated Battenberg cake. Neither is she afraid to discuss important political and rights-based questions around equality… This book is a wonderful refutation of that misconception. Exploring the meaning of “equals” in mathematics gives us a better understanding not just of the nuance and richness of the field, but of how ideas of equality are used (and misused) in life.” —New Scientist

"Eugenia Cheng has opened up my mind to the wondrous world of pure mathematics in a way that I never thought was possible."—Willow Smith, singer and actress

"Eugenia Cheng's writing is generous and precise, a soft-serve swirl of the universal and the particular. In a way that few mathematicians can, she writes for everyone."—Ben Orlin, author of Math with Bad Drawings

"Eugenia Cheng has done it again. Not only is she a great teacher of powerful mathematics: she shows us how understanding math can help us live better lives. Once you read this book, you'll have a new perspective on equality and difference, and why both matter so much."—Stephon Alexander, author of The Jazz of Physics

"Eugenia Cheng has done it again! With her usual brilliance she has caused us to question all that we thought was true about mathematics."—Jo Boaler, author of Math-ish

"Eugenia Cheng has humour, grace and a natural gift"—Daniel Levitin, author of I Heard There Was a Secret Chord

"Clear, clever and friendly...even at her most whimsical, she is rigorous and insightful" —Alex Bellos, author of The Grapes of Math

Product Details

BN ID: 2940194555352
Publisher: Hachette Audio
Publication date: 09/02/2025
Edition description: Unabridged
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