Leo the Rabbit has become a Youcubed favorite. It is a great problem for using creativity to illustrate and justify student thinking and it leads to rich class discussion.
Leo the Rabbit is climbing up a flight of 10 steps. Leo can only hop up 1 or 2 steps each time he hops. He never hops down, only up. How many different ways can Leo hop up the flight of 10 steps? Provide evidence to justify your thinking.