Thanks to author Keith Devlin’s generosity, I am giving away FIVE copies of his new e-book Leonardo and Steve: The Young Genius Who Beat Apple to Market by 800 Years (at the end of this review post), PLUS a signed copy of his latest print book, The Man of Numbers: Fibonacci’s Arithmetic Revolution.

What Leonardo did was every bit as revolutionary as the personal computer pioneers who in the 1980s took computing from a small group of “computer types” and made computers available to, and usable by, anyone. Like them, most of the credit for inventing and developing the methods Leonardo described in **Liber Abbaci*** goes to others, in particular Indian and Arabic scholars over many centuries. Leonardo’s role was to “package” and “sell” the new methods to the world.

The appearance of Leonardo’s book not only prepared the stage for the development of modern (symbolic) algebra, and hence modern mathematics, it also marked the beginning of the modern financial system and the way of doing business that depends on sophisticated banking methods.

— Keith Devlin

Fibonacci’s ‘Numbers': The Man Behind The Math

excerpt from **The Man of Numbers**

* Leonardo of Pisa, also known as Fibonacci, used two b’s in the word “calculation” (*abbaci*) to distinguish his methods from the use of an abacus.

## Can You Solve This Fibonacci Puzzle?

If you want a chance to win a personally signed copy of *The Man of Numbers: Fibonacci’s Arithmetic Revolution*, all you have to do is solve this riddle.

Email me your answer.

Do NOT give your answer as a comment here! If that email link doesn’t work for you, then copy my address by hand: lets play math [no spaces] at gmail dot com.

**Here is the puzzle:**

The Fibonacci sequence arises in the solution to a problem about a breeding rabbit population that Leonardo gave in **Liber Abbaci**.

But there is evidence that in another book he gave the problem in terms of different creatures. **What were they?**

[Hint: The answer is in the e-book, *Leonardo & Steve*. But this is a no-purchase-necessary contest: There are at least two places to find the answer online, if you search carefully.]

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