What is the religious diversity of the world? Of the United States? In this investigation, sixth grade students explored these questions (and raised many more). Using Pew Center's religious diversity index and data, we explored the diversity of the world.  Afterwards, small groups of students analyzed religious diversity of one state and then we put together a map of the United States to analyze the religious diversity of the country. In this process, students learned about scale, proportions, mathematical modeling – and communicated these ideas and concepts during their presentations.