Mathella in Oz (or Mexico): The Ins and Outs-Calculating Area and Perimeter

In this adventure, Ella falls asleep while watching the Wizard of Oz. Somehow, she finds herself in Mexico where she meets Charro, who needs to keep his cattle inside a certain area, and the twins, Peri and Meter, who can only play outside or around the fence. By using math, Ella helps them solve their problems, but it will require teamwork for her to get home.