Fourth grade and Algebra 1 mathematicians recently teamed up to celebrate Pythagorean Triple Square Day, a once-in-a-century math milestone! On Tuesday, September 16, 2025 (9/16/25), the date is the lesson because each number representing the month, day, and year is a perfect square (3², 4², and 5²), and together they form a Pythagorean triple since 3² + 4²=5². To mark the occasion, fourth graders in Math Department Chair Maura Oare’s class joined forces with Christina Berthelsen’s Upper School Algebra 1 Part 1 students to dive into perfect squares, explore Pythagorean triples, and share a sweet square treat at the end.

After learning about perfect squares, and how a date can be a perfect square without forming a Pythagorean triple, students were challenged to identify the next ten perfect square days after 9/16/25, as well as the next perfectly square year. Fourth graders teamed up with the older Algebra 1 students to brainstorm strategies, develop algorithms, and test their ideas for finding each square number in the sequence. To make the math tangible, students cut out grid squares and used Starburst candies as manipulatives to build their own perfect squares. They discovered that the interiors of three consecutive perfect squares naturally form a right triangle. By shading each square in a different color, they could see the relationships and patterns emerging - squares inside squares! 

The class wrapped up by sharing the Starburst squares as a sweet reward. Beyond the treats, this collaboration gave the fourth graders an engaging preview of concepts they’ll encounter as they grow as mathematicians and the older students the opportunity to appreciate mathematical patterns and share their understanding with younger classmates. It’s also just the start, as these two classes will be teaming up for more math explorations throughout the year.