Regular price: $19.95

Free with 30-day trial
Membership details Membership details
  • A 30-day trial plus your first audiobook, free
  • 1 credit/month after trial – good for any book, any price
  • Easy exchanges – swap any book you don’t love
  • Keep your audiobooks, even if you cancel
  • After your trial, Audible is just $14.95/month
Select or Add a new payment method

Buy Now with 1 Credit

By confirming your purchase, you agree to Audible's Conditions of Use and Amazon's Privacy Notice. Taxes where applicable.

Buy Now for $19.95

Pay using card ending in
By confirming your purchase, you agree to Audible's Conditions of Use and Amazon's Privacy Notice. Taxes where applicable.

Publisher's Summary

What is the missing variable?
Alex, a young precocious girl, mysteriously gets transported to a strange world where Latin and Math combine in formulas and equations with magical effects. With a cruel council leading the only safe city of its kind in this world, she will have to prove her worth to stay as well as help this city as it is the target for two evil wizards who seek to destroy the city and its ruling council.
Will the council's mighty army of guardians be enough to repel the onslaught of the two wizards' wrath? To help the city and also get back home, she will need the help of the greatest mathematician of all time, Archimedes. In a world where math is magic, Alex wishes she paid more attention in math class.
©2014 Jim West (P)2015 Jim West
Show More Show Less

Customer Reviews

Most Helpful
5 out of 5 stars
By Cindy Rice on 05-14-15

Entertaining story

Where does Libellus de Numeros rank among all the audiobooks you’ve listened to so far?

pretty high, I would give it a 9/10.

What did you like best about this story?

Oh there were a handful of things I liked. I personally HATE math, I want to stab it (I burned my last math book in college.) This book gave me a NEW appreciation for math, I love the concept that magic is only possible through math. I also love the idea of the ranking system of the 100 guardians. I also like that Alex grows in the story, she is figuring out how to be on her own in a way without her father there and in her missing him regrets how she treated him the last time she saw him. I like that Alex is smarter then the other kids in the class and that her being female and smart is something valuable for her with the high counsel looking down on women and forcing them to be silent when they are in the court area.

What does TJ Maggio bring to the story that you wouldn’t experience if you just read the book?

The voices for each character add so much to the story, especially Archimedes voice. The way the voices were narrated gives it such a vibrant edge.

Was this a book you wanted to listen to all in one sitting?

yes, and I did.

Any additional comments?

I really hope the following books are made into audio books. I am curious and want to know what happens next. I do feel there was closure with this book, however Alex isn't home yet so there has to be more.

Read More Hide me

3 of 3 people found this review helpful

5 out of 5 stars
By Tracie on 10-10-16

Awesome book, my 11 year old couldn't put it down

If you could sum up Libellus de Numeros in three words, what would they be?

Exciting, thrilling and awesome

What was one of the most memorable moments of Libellus de Numeros?

When Alex shattered the 2 ton boulder

Did you have an extreme reaction to this book? Did it make you laugh or cry?

Just excitement to read the next book.

Any additional comments?

My son wouldn't leave me alone until I downloaded the second book for him.

Read More Hide me
See all Reviews
© Copyright 1997 - 2018 Audible, Inc