# Fibonacci Day!

Numbers make patterns, and one of the most interesting patterns is the Fibonacci series: you start with 0,1, and each number is the previous two numbers added together. So 0+1 gives us 1, and then 1+1 is 2, then you add 1+2 to get 3, then 2+3 to get 5, then 3+5 to get 8, 13, 21, 34…and so on. Today is Fibonacci Day, because the date is 11/23 (1-1-2-3). Lots of objects in nature grow in shapes driven by Fibonacci numbers: snail shells spiral around these numbers, and the seeds in the middle of a sunflower, and even the hair on your head!

Wee ones: Can you remember the set of numbers 1, 1, 2, 3, 5, 8? See if you can say it back!

Little kids: Which is bigger, the jump from 3 to 5, or the jump from 5 to 8?  Bonus: What’s the next number in this pattern: 1, 3, 5, 7, 9…?

Big kids: What’s the next Fibonacci number after 34?  Bonus: For any Fibonacci number from 3 onward, which is bigger, 2 times that number, or the next Fibonacci number?

The sky’s the limit: If we look at just the single-digit Fibonacci numbers, how many dates this year had some set of consecutive Fibonacci numbers in the right order? (Just look at month and day, and in that order.)