As Head of School Jennifer Borman ’81 mused in her opening remarks, all of our current students, faculty, and staff  “make up the 2025–2026 version of Commonwealth, one that has never existed in this exact way before.” This version is our biggest yet, with an enrollment of 163 students. As we continue to challenge ourselves and each other to learn the names of every one of those students, take a moment to meet some of the new faces joining Commonwealth’s faculty and staff this year.

Ben Roberts, English and History Teacher

Mr. Roberts earned his joint degree in Comparative Literature and History from Harvard University. He then taught at John Burroughs School in St. Louis, Missouri while earning a Masters of Science in Education through the University of Pennsylvania. Mr. Roberts teaches both history and English. Outside of the classroom, he loves rowing, film photography, and movies.

Mira Bernstein ’89, P’20, Math Teacher

Ms. Bernstein is a Commonwealth alumna (Class of 1989) and parent (Class of 2020). She is delighted to be back at the school for a year as a sabbatical leave replacement. Ms. Bernstein received her Ph.D. in algebraic geometry in 1999 and has taught at UC Berkeley, Stanford, and Wellesley College. She has been one of the key organizers of Canada/USA Mathcamp, an international summer program for mathematically talented high school students, since 1997 and was a founding faculty member and admissions director at Proof School in San Francisco in 2015. Ms. Bernstein has also contributed to a number of projects in data science and statistics. Her focus has been on applying mathematics to issues of social importance, such as voting rights and the effects of extending health insurance to the uninsured.

Lilah Mercadante, Science Teacher

Ms. Mercadante recently received a M.A. in physics from Boston University and is beginning her journey in teaching formally at the high school level. She earned her B.A. in physics and astronomy from Smith College, where she graduated with High Honors and was awarded a prize from the physics department for her academic achievements. During her academic career, she focused on computational astrophysics research spanning the fields of gravitational wave physics, exoplanet detection, and analysis of supernova data. In her free time, she enjoys reading, board games, baking, and playing the piano and ukulele.

Meet More Commonwealth Faculty and Staff