What exactly IS an ISBN lookup number?

We’ve all seen it before, and probably a lot of us have even used it to find our textbooks. Our professors and syllabi often state it, and we always see it when we are checking out of an online bookstore…. but what exactly IS an ISBN number?

For those who are completely unfamiliar, the ISBN number stands for ‘International Standard Book Number’ and it is a unique identifier assigned to every book to help identify that book. There are actually two different types of ISBN numbers, the ISBN-10 consisting of 10 alpha-numeric characters and the ISBN-13 which has 13 alpha-numerics. Using this number anyone can easily find the textbook they are looking to buy on online bookstores like Textbook Nova and many others; and if you do not use the ISBN lookup feature then you can at least use this number to be confident that you found the correct textbook that is required for your class. Fortunately every new edition and format (ebook, hardcover, softcover, etc) is assigned a new ISBN, so if you are using an ISBN lookup to find your textbooks you can be positive you got the right edition.


In 1967 Gordon Foster realized that we needed a system to uniquely identify books, and a nine-digit number was invented called the Standard Book Numbering (SBN) system. However, shortly after the International Organization for Standardization (commonly known as ISO) published an article called ISO 2108 in 1970 which introduced the ISBN-10 we know of today. Fortunately they were smart enough to realize that a lot of books would be missing from this index, so any book that existed before the ISBN was introduced can still be referenced by it’s nine-digit SBN number preceded by a zero (thus the ten characters required to make a valid ISBN-10.

Any textbook that was assigned an ISBN number assigned after January 1st, 2007 was assigned an ISBN-13 number.

What makes an ISBN?

Every ISBN number consists of at least four parts, and ISBN-13 will include a prefix “EAN” number that is provided by GS1 which is an international non-profit organization. As of this writing the only “EAN” numbers that have been provided are 978 and 979, but as more books are published eventually they will assign a new EAN number for those books.

The next 4 numbers specifies the “Registration Group Element” which is a language specific code that identifies the country or territory that the textbook was registered.

Then there is the “Registrant Element” or the publisher code. The national ISBN agency keeps track of all the publishers and has assigned each of them a specific code that they use. At this time they have more than 900,000 registered publisher codes.

The title of the book is the next section also called the “Publication Element”. Large book publishers will often receive a block of ISBN codes and when they publish a book they assign the title of the book to a specific Publication Element code.

Finally there is a “Checksum” which is a number that is calculated to validate the ISBN number.

Validation of an ISBN

If you are having trouble doing an ISBN lookup for a textbook it could be for one of 3 reasons… Either 1) You are typing the wrong number into the search bar, 2) The search you are using does not work or 3) The person who gave you the ISBN number typed it wrong. If you suspect that the ISBN number you have is not valid you can always calculate the checksum digit yourself on the number to validate it and make sure that there is actually a textbook with that assigned ISBN number. Here’s how:

For an ISBN-10 with ten digits:

  1. Multiply the very first digit by 10 (if this digit is the character ‘X’ it should be counted as 10)
  2. Multiply the second digit by 9 (again, if this second digit is ‘X’ count it for the value of 10)
  3. Multiply the third digit by 8
  4. Repeat this process by multiplying the next number by one less than the previous
  5. Once you get to the right most digit (the one that will be multiplied by 1), add all of these digits together.
  6. Now you will need to perform a Modulo, which is fancy-math term for “Find the remainder”. Take the large number you just added and divide it by 11 and find the remainder of that number. The result of your modulo operation should not be a fraction, if you just did this in a calculator you just need to multiply that fraction by 11 to get the modulo.
  7. Now that you have your modulo, subtract it from 11 (“11 – your result”).
  8. Finally perform one more modulo operation with your number to get the Checksum digit (remember if you ended up with 10 it should be considered X in this case)

For an ISBN-13 with thirteen digits:

  1. Every other number is multiplied by 3, starting at the second digit. The easiest way to do this is by multiplying the second digit by 3, and adding it to the first digit.
  2. Repeat this process until you are down to the last digit again (your next operation will be multiplying the fourth digit by 3 and adding it to the third digit.)
  3. Add all of these numbers together, and perform the Modulo 10 operation (See above for an example on how to perform the modulo, just remember we are doing modulo 10 here, not modulo 11).
  4. Finally subtract your result from 10 to get the Checksum digit (“10 – your result”). The ISBN-13 is special in that if you end up with the number 10 for your checksum digit, it is represented by the number 0 (unlike the ISBN-10 where 10 is represented by ‘X’).

Whew! That was a lot of math, but it’s over now! There is a lot more to learn about ISBN numbers, but hopefully this will give you an idea of why it is important and how it can be beneficial when you are buying textbooks for your classes. Remember you can always be confident that you have found the correct book if you use an ISBN lookup like the one provided by Textbook Nova. Please feel free to reach out if you have questions or any corrections to this post.

The six best Mathematics textbooks that will blow your mind

If you are interested in buying the right textbook for mathematics online, then you need to check out our collection of the six best mat textbook that are specifically written for students in college. Mathematics, in general, is the study of things like numbers, structure, space and change. Math is a subject that is essential for everyone in the world. The basic mathematical operations include addition, subtraction, multiplication and division and there’s an extremely good chance that we use all four of these on a daily basis! So it is essential to know the basics as well as the more advanced uses of mathematics. Math is taught to students from their early school years up to their final degree years and further. So lets have a look at our collection of six best mathematical college textbooks.

1. Finite Mathematics for Business, Economics, Life Sciences, and Social Sciences, 13th Edition

This mathematics textbook is for students in the freshman or sophomore year. The book is specially designed to help students help themselves excel in the course. The book offers more guidance than any other in the online book market. This textbook provides a better learning and teacher experience as it feature the MyMathLab addon. This supplements the course with online homework and learning tools that helps any student when learning the course. There are more than forty-two thousand exercises in this textbook which help a student prepare for their tests and exams that may come in a course requiring this textbook.

2. College Mathematics, 9th Edition by Cleave and Hobbs

College Mathematics is specially designed for students in the college freshman or sophomore year. The book explores common courses like business, social science, economics, and life sciences. This college textbook is designed to help students succeed in any course that requires this material. This textbook has more guidance embedded in it than any other textbook in the online books market. The book provides a better learning and teaching experience than many others, and as an added bonus it also includes MyMathLab.

3. Algebra for College Students

The book covers the basics of algebra for any college student. The writer, Bob Blitzer, uses realistic applications in his textbook and makes it easy for anyone to understand. This overview develops curiosity among students about the mathematical concepts of the world. Topics included in the textbook are relevant to the college course and level of understanding. These topics are mostly pulled from recent pop culture and everyday life that ensures that students will really use their learning skills to achieve success. This book is also accompanied by MyMathLab, which enables students to get their homework done online along with many other learning features.

4. College Algebra and Trigonometry by Margaret L. Lial

College Algebra and Trigonometry consists of four courses of algebra and trigonometry. This textbook combines the experience of master teachers to help students develop both the analytical skills and conceptual understanding necessary for success in math classes. Algebra and Trigonometry are two major courses so it is important to choose a well written book like this one. MyMathLab also accompanies this book like many of the others. This feature helps students assess their understanding of the programs that are specially designed to work with this book’s course. This makes students practice more and more to have a better understanding of their courses concepts of algebra and trigonometry.

5. Calculus: Early Trancendentals, 2nd Edition

The book is designed for a three-semester or four-quarter calculus course. This textbook covers single-variable and multi-variable calculus intended for mathematics, engineering and most scientific majors. This Calculus textbook is the most successful text published in the last 20 years. The writers Briggs, Cochran and Gillett draw students in to the narrative through the writing that reflects the voice of an instructor. Examples are narrative and symbolic and figures are designed in a way that teaches students can help to understand the core concepts of Calculus. MyMathLab also accompanies this college textbook like the others. This book offers a high quality teaching and learning experience through the organization and preparation of content that facilitates learning.

6. Math Lit, 2nd Edition

Math Lit college textbook provides a one-semester alternative to the traditional two semester algebra sequence for non-STEM students. This basic approach offers students an accelerated pathway to college readiness through developmental math. Preparing students to move directly into introductory statistics, liberal art math and intermediate algebra. This book also contains the MyMathLab with the same features as of any book that is accompanied by this software.

These books are some of the best books for mathematics students in college. These books cover courses from basic mathematics to career selection courses and all of these books are readily available at books online stores and in the market.

Five mistakes to avoid when buying textbooks online

Often times people whoare trying to buy the textbooks they need for their classes, they will make a mistake…. and often times a very costly mistake. Textbooks can be expensive and places that buy books back from you often will give you a mear fraction of what you paid. You’d be lucky to find a place that will give you your money back within 30-days, but even then if you have purchased your books well in advanced (like the punctual person you are!) then you might not be able to refund all the money you just spent. Here are the most commonly made mistakes when purchasing books online:

  1. Make sure you get the right version. It’s extremely common practice for textbook publishers to keep the same cover to a textbook when they change editions, so if you are purchasing a book online make sure you confirm that you are looking at the correct edition for your class… don’t assume just because it looks like the right book that it is. And always remember, “don’t judge a book by it’s cover”
  2. Fail to use the ISBN search. Textbook stores like textbooknova.com and a few others allow users to search for their book based on the ISBN (either a 13 or a 10 digit number to uniquely identify a book). Using an ISBN search is the number one most accurate way to find your textbooks, and if you are on a website that doesn’t allow you to do ISBN look-ups, don’t even bother spending any more of your time (or money) on that marketplace!
  3. Fail to match the title of the textbook. Another frequently made mistake among textbook buyers is that they do not match the exact title that is required for the class. There could be a billion textbooks called “Chemistry” but if your class needs the book “Earth Chemistry” or any variation like that then you need to make sure you are looking at buying the correct book.
  4. Price shop around! Often you will be able to find the correct book, but if you fail to attempt to find your book at a few other marketplaces, you might end up spending way too much money! Make sure you do your due diligence to find the marketplace with the best price for the textbook before you buy it online. Fortunately for you, if you are searching Textbook Nova then you can rest assured that we offer some of the most competitive prices available.
  5. Buying a used copy without checking for the quality. You wouldn’t believe how many times I’ve tried to save money by purchasing a used textbook, only to find out half way through the semester that someone had torn pages out on an important chapter. How many times have you seen someone bored in class doodling inside their book? Who even knows where that textbook has been! If you are buying used textbooks online, make absolutely sure you can check to see the quality of the used book and try to find the ones closest to new.

We hope these tips have been helpful for anyone purchasing books online, and hope you have a great semester of classes!