chalkdust Liber Abaci made Leonardo of Pisa famous. He aracted the aention of the Holy Roman Emperor, Frederick II, who was renowned for his thirst for knowledge. The two men wrote to each other for many years, and Fibonacci published more matheFibonacci’s legacy is visible to matical works, building on those first steps in Liber each and every one of us, every Abaci. Once the printing press was introduced to single day. Europe in the 15th century, the use of the Hindu– Arabic number system spread even further. Fibonacci’s legacy is visible to each and every one of us, every single day. It’s not in the number of petals on a flower, or spirals on a pine cone: it’s the numerals themselves. I for one think that’s an amazing gi to bestow. Solution to the bird problem Let x = partridge, y = pigeon and z = sparrow, so the problem gives us two equations: x + y + z = 30, 1 3x + 2y + z = 30. 2 We know that the values of x, y and z are actual birds, so must be positive whole numbers, and can’t be zero. Doubling the second equation and subtracting the first to eliminate z gives: 5x + 3y = 30.
19th century statue of Leonardo Fibonacci in the Old Cemetery, Pisa.
Now look at this last equation. The 5x and 30 both divide by 5, so it must also divide 3y. Therefore, y is a multiple of 5. But it can’t be 10 or larger else the last equation won’t work: x cannot be zero. So y = 5,
x = 3,
and z = 22.
Emma Bell is a maths teacher at Franklin College in Grimsby, UK. You can follow her on Twier @El_Timbre, and email her at email@example.com
Further reading The Man of Numbers: Fibonacci’s Arithmetic Revolution by Keith Devlin