Leonardo Pisano (Fibonacci)

Life: Travels shaped my mind like clay in a potter's wheel.

Comeback: Your doubt multiplies my determination.

Field: Algebra unlocks the secrets of the unknown.

Meaning: In the end, all sums to the greater design.

If someone asks you to divide 10 into two parts, one of which is 3/4 of the other, you should say that the first part is 4 and the second is 6.

A certain man put a pair of rabbits in a place surrounded on all sides by a wall. How many pairs of rabbits can be produced from that pair in a year if it is supposed that every month each pair begets a new pair from the second month on?

I have been led to this by the desire to do something useful for the merchants of the Pisan Republic, and for others who wish to learn the art of calculation.

The nine Indian figures are: 9 8 7 6 5 4 3 2 1. With these nine figures, and with the sign 0 which the Arabs call zephyr, any number can be written.

And so that the Latin people should no longer be without the knowledge of this art, I have published this book.

For if one knows how to add, subtract, multiply, and divide, then all other calculations are easy.

From this knowledge, one can solve all the problems of merchants, and others who deal with numbers.

The more one practices, the more proficient one becomes.

And thus, by this method, one can find the solution to any problem of this kind.

I have shown how to calculate with whole numbers and with fractions, and how to extract roots.

For those who wish to learn, I have written this book in a clear and simple manner.

And if anyone finds an error, they should correct it, for no one is perfect.

The art of calculation is very useful and necessary for all men.

And so that this knowledge should not be lost, I have committed it to writing.

For the sake of brevity, I have omitted many things that are obvious to those who understand the principles.

And I have taken care to explain everything with examples, so that it may be easily understood.