Gilly and the rest of the castaways have been stranded on different islands. To rescue them, your students will have to calculate the area and/or perimeter of the islands! One activity will require algebraic thinking. Students will have to calculate the missing measurement of the length of one side of an island to discover what item the castaways will find to help them survive while stranded. Three separate card decks for three separate activities. Easily differentiated based on what you are learning -- perimeter, area, or both. Suggestions for advanced learners as well. Great activities for centers.