Upper School Math Department Head Suzanne Lee resigned from the school effective immediately, Head of School Laura Ross announced in an email to her students Jan. 1.

Lee resigned for personal reasons, according to Ross. During Lee’s tenure at the school, she taught math classes for over 20 years and was appointed department chair in 2016. She also served as student council adviser from 2002 to 2007.

“She’s OK and her family’s OK, but it is her decision for personal reasons to step away mid-year, which obviously is a disruption for her students and for her department since she is department chair,” President Rick Commons said.

Lee did not respond to The Chronicle’s request for a comment.

Math teacher and head of the Faculty Academic Committee Kent Nealis will step in as interim department head, and several math teachers will take over Lee’s AP Calculus BC 11, Introduction to Calculus Honors and Precalculus: Trigonometry and Functions classes.

As interim department head, Nealis will focus on organizing placement tests and course selections toward the end of the year, as well as having general oversight of the department. He said transitioning into his new position has not been especially difficult so far because of his long tenure at the school.

“This is my 27th year here, so I’m obviously well-trained with how things run,” Nealis said. “I’ve been the FAC chair for a long, long time so I have a pretty deep understanding of how departments run, and I’m familiar with all the people here who can help you get the job done.”

He said the entire math department has adjusted well to the unplanned resignation, complimenting the flexibility and helpfulness of his colleagues.

“The transition was nearly seamless,” Nealis said. “That’s the advantage of having really good people, you can do things like this without having too much disruption.”

Math teachers Laffite Lamberto-Egan and Woo Sim are teaching Lee’s Introduction to Calculus Honors classes, math teacher Kasia Williams took on the AP Calculus BC 11 section and math teacher Adam Varney is teaching Lee’s former Precalculus: Trigonometry and Functions class.

All teachers filling in for Lee are already teaching the courses in other sections this year, which made the transition much easier, Nealis said. The only teacher taking on a new course is Williams, who will now be teaching the only section of AP Calculus BC 11. Nealis said Williams is well-acquainted with the material from her experience teaching AP Calculus BC 12.

“I can understand that her former students are going to feel somewhat uncertain about this unexpected turn of events, but we are so fortunate to have a talented and committed math department faculty to draw upon as we go forward,” Nealis said. “I can confidently speak for the entire math department in saying we are going to work tirelessly to assure that we fully meet the needs of our students.”

Commons said he appreciated Nealis’ willingness to step in on such short notice as interim department head.

“It’s obviously not going to be without a little bit of disruption, but because we have internal people handling the transition I feel confident, as do [Ross] and [Nealis], that we’re taking as good care of the students as we can,” Commons said.

Despite initial confusion, some of Lee’s students said the transition in their math classes has been smooth.

“I think the department has dealt with it quite well,” Anja Clark ’19 said. “[Varney] has been really good about saying, ‘If there’s anything I do differently from Ms. Lee, tell me.’ I think [the math department] is definitely doing what they can to make it as seamless as possible and so far it’s working pretty well.”

Clark said she is still curious to learn about the reasoning behind Lee’s departure.

“I definitely respect that she wants her privacy, but I also think I would appreciate some more information just because it is a bit weird the day before school starts to suddenly have a new teacher,” Clark said. “A bit of explanation would be fine but I definitely respect the fact that stuff needs to be kept private.”

The administration decided against bringing in a new faculty member mid-way through the year since it could make Lee’s students’ transition more difficult, Ross said.

The school plans to hire a new math teacher for the next school year.