Spring is here, and that means our friends the flowers are just around the corner. What’s cool is that some flowers do math without even knowing it! Sunflowers always have a certain numbers of petals — only some numbers can work. There’s a special set of numbers where you get each number by adding the 2 numbers before it. You start with 1 and 1, which gives you 2…then 2+1 is 3…then 3 plus that 2 gives you 5…5 plus that 3 gives 8, and so on. They’re called the Fibonacci numbers, and sunflowers always have a Fibonacci number of petals! Let’s see how big that flower can get.

*Wee ones:* If the first few Fibonacci numbers are 1, 2, 3 and 5, which number did we skip that we would have said if counting?

*Little kids:* If the last 2 Fibonacci numbers we got were 5 and 8, what’s the next number? (Reminder: You get each number by adding the previous two numbers.) *Bonus:* If you have a flower with that many petals and another with 5 petals, how many do they have together?

*Big kids:* Can a sunflower have 25 petals? *Bonus:* For fun we also have “Tribonacci” numbers, where you add the last 3 numbers to get the next. Since it also starts with 1, 1, and 2, what are the next 3 Tribonacci numbers? See if you can remember all the pieces in your head!

Answers:

*Wee ones:* 4.

*Little kids:* 13. *Bonus:* 18 petals (13 + 5).

*Big kids:* No, because after 21 we add 21 + 13, which is 34. *Bonus:* 4, 7, and 13.