🎬 Step 1: Watch the video first!
An 8-minute animated video in 13 short levels. Press START and turn your sound on! When you're done, scroll down and start the lesson. 👇
Video not showing? Open it in a new tab.
Meet Fibonacci!
About 800 years ago, in the year 1202, an Italian mathematician named Leonardo of Pisa (nicknamed Fibonacci) wrote a famous book called Liber Abaci, "The Book of Calculation." In it, he asked a puzzle about rabbits... and the answer was this sequence:
🔑 The rule
Start with 1, 1. Then each new number is the sum of the two numbers before it.
1 + 1 = 2 · 1 + 2 = 3 · 2 + 3 = 5 · 3 + 5 = 8...
🇮🇳 Fun fact: Mathematicians in India discovered this same pattern hundreds of years before Fibonacci, while studying the rhythms of poetry!
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How Fast Can Rabbits Multiply?
Fibonacci's original puzzle from 1202.
Fibonacci imagined some very special (make-believe) rabbits:
🐇 = grown-up pair · 🐰 = baby pair
🔮 Prediction game
Before you click past it: How many pairs will there be in month 10?
The Bee Family Tree
"Who are my ancestors?"
Honeybees have a surprising family rule:
The Sunflower Spiral
"Can you find the pattern?"
Look closely at the seeds in a sunflower. They aren't in rows. They're arranged in spirals going two directions! Many sunflowers have 34 spirals going one way and 55 going the other. Both are Fibonacci numbers!
🔍 Find the spirals
Click any seed to light up the spiral it belongs to. Find at least 5 spirals each way!
Add them up!
The sunflower has 34 clockwise and 55 counterclockwise spirals. 34 + 55 = ?
How Many Petals?
Observe → find the pattern → explain.
Click a flower to zoom in. Then click each petal to count it. Count all 6 flowers!
What do these flowers have in common?
Leaves on a Plant
"Why are the leaves arranged this way?"
Scientists who study how leaves are arranged call it phyllotaxis (fill-oh-TAK-sis), which means "leaf arrangement." Many plants turn about 137.5° between each new leaf. This is called the golden angle, and it's connected to Fibonacci numbers!
Turn between leaves:
Leaf quiz
Build the Fibonacci Spiral
Put the squares in order and watch the spiral appear.
Click the squares in Fibonacci order: 1, 1, 2, 3, 5, 8, 13. Each one gets attached to the growing shape.
Does this spiral appear in nature?
The Golden Rectangle Builder
Fibonacci numbers → the golden ratio
✨ As the numbers get bigger, the ratio gets closer and closer to 1.618..., called the golden ratio. The digits go on forever without repeating!
Golden ratio quiz
What's Missing?
They get harder as you go!
Is This Really Fibonacci?
Think like a scientist, not a fan!
Lots of websites and videos say "Fibonacci is EVERYWHERE in nature!" But a good scientist asks: Is that actually true? Some examples are real, some are myths, and some are... complicated. Decide for each one!
Build the Sequence
Start with 1, 1 and keep adding until you reach 196,418!
The rule never changes: add the last two numbers to get the next one. Type each next number. The numbers get BIG, so use the calculator right here. Reach 196,418 to earn the badge.
The Fibonacci Challenge Room
Escape the room by solving every level!