---
product_id: 10076651
title: "100 Essential Things You Didn't Know You Didn't Know: Math Explains Your World"
brand: "john d. barrow"
price: "$995"
currency: MXN
in_stock: true
reviews_count: 13
url: https://www.desertcart.mx/products/10076651-100-essential-things-you-didnt-know-you-didnt-know-math
store_origin: MX
region: Mexico
---

# 100 Essential Things You Didn't Know You Didn't Know: Math Explains Your World

**Brand:** john d. barrow
**Price:** $995
**Availability:** ✅ In Stock

## Quick Answers

- **What is this?** 100 Essential Things You Didn't Know You Didn't Know: Math Explains Your World by john d. barrow
- **How much does it cost?** $995 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.mx](https://www.desertcart.mx/products/10076651-100-essential-things-you-didnt-know-you-didnt-know-math)

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## Customer Reviews

### ⭐⭐⭐ 







  
  
    There's a reason you didn't know you didn't know
  

*by J***S on Reviewed in the United States 🇺🇸 on February 12, 2014*

I want to like this book. I really do. I feel as if I'm admitting some sort of intellectual bankruptcy in saying: It's too much. I think it would be over most people's heads. Maybe it's just me??For instance, no copyright infringement intended, but here is part of section 28:"Let's pick the annual rainfall in the UK as our example. In the first year that we keep records the rainfall must be a record. In year two, if the rainfall is independent of what it was in year 1, then it has a chance of 1/2 of being a record beating the year 1 rainfall and a chance of 1/2 of not beating the rainfall. So the number of record years we expect in the first two years is 1 + 1/2. In year 3 there are just two ways in which the six possible ranking (i.e. a 1 in 3 chance) of rainfall in years 1, 2 and 3 could produce a record in year 3. SO the expected number of record years after 3 years of record keeping is 1 + 1/2 + 1/3. If you keep on going, applying the same reasoning to each new year, you will find that after n independent years of gathering data, the expected number of record years is the sun of a series of n fractions: 1 + 1/2 + 1/3 + 1/4 +... 1/nThis is a famous series that mathematicians call the 'harmonic' series. Let's label as H(n) its sum after n terms are totalled; so we see that H(1) = 1, H(2) = 1.5, H(3) = 1.833 ... and so on. ... What does this tell us? Suppose that we were to apply our formula to the rainfall records for some place in the UK from 1748 to 2004 - a period of 256 years. Then we predict that we should find only H(256) = 6.12, or about 6 record years of high (or low) rainfall. If we look at the rainfall records kept by Kew Gardens for this period then this is the number of record years there have been. We would have to wait for more than a thousand years to have a good chance of finding even 8 record years."Maybe it's just me, but I would looking for a coffee table/bathroom book that would be full of interesting little factoids that people could share in 2 minutes WITHOUT a pencil and paper.I also ordered "I wish I knew that Science" and that is much more what I was looking for. If you and your audience are more on the academic side, this might work, otherwise I'd go with the "I wish I knew that" series.

### ⭐⭐⭐ 







  
  
    Good Bathroom Reading
  

*by A***R on Reviewed in the United States 🇺🇸 on August 15, 2010*

It seems the author has finally exhausted the list of topics he covers so well in his other books. This is a good book for reading in the bathroom but not for much else. It's a compilation of short articles covering a wide range of topics with nothing to connect them so it lacks focus. The very British writing directed at the British reader makes some of the articles rather plodding and requires a grip of the vernacular to understand what the author is on about. Some of the information is just plain wrong - his description of "Why Does the Other Queue Always Move Faster?" rambles around but never does get to the answer - if there are four lines and you pick one, you have only a 25% chance of joining the fastest line/queue (and a 75% chance of the "other" line moving faster). Some of the information manages to make relatively simple concepts unnecessarily dense through the use of mathematical formulas where descriptions would add clarity. Mildly amusing but don't look for anything even close to the "Essential" mentioned in the title. But one wouldn't be reading this in the bathroom if one were seeking revelation, would one? I would truly enjoy hearing the topics covered in this book from the author over a pint (or two) at the pub. He just should not have tried to write it down and publish it as it detracts from his other writings.

### ⭐⭐⭐⭐⭐ 







  
  
    A treasure for math trivia, entertainingly written
  

*by W***T on Reviewed in the United States 🇺🇸 on September 1, 2009*

Professor Barrows takes a slight diversion from his recent books, by assemblying 100 precis-like mathematical topics for one' s amusement. Each topic is no greater than a couple of pages, and makes incremental reading (such as while at an airport or train/subway station) convenient. His style is easy to digest, and his introductory quotations aptly ensconces the topics to be discussed. For those wanting more background or details, most of the topics are footnoted at the back of the book.This book is a fun read for any mathematics afficionado.

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*Product available on Desertcart Mexico*
*Store origin: MX*
*Last updated: 2026-02-22*