Dagmar Kilp was preparing her fifth-grade class in Orlando, Fla., for annual state exams. She was trying to make it engaging for students with an “amazing math race,” but she was also feeling worn down.

“It was one of those days I was thinking maybe I should just step away from teaching,” said the 15-year veteran of Orange County Public Schools.

Then a crowd of people, some with cameras, entered her classroom along with a teenager who looked vaguely familiar.

“Oh, my gosh,” Kilp thought, “that’s little Hannah.”

Hannah Juda, now 18, was Kilp’s student in third grade and fifth grade, and was set to graduate from Lake Nona High School.

In a tradition that began six years ago, Juda’s last English class assignment — a voluntary one — was to write a thank-you letter to an elementary or middle school teacher who had helped her.

She was one of nearly 6,000 OCPS 12th graders — about half the district’s graduating seniors — who wrote thank-you letters this year as part of “Project Impact,” an effort to recognize graduation as a “K-12 experience,” said Harold Border, the district’s chief of high schools.

“Every time a kid walks across the stage that represents many, many teachers and staff members who helped them get there,” Border said.

In her letter to Kilp, Juda wrote of her struggles on third-grade spelling tests because she couldn’t always hear the words said out loud. Kilp moved her seat so she’d be close to her and better able to understand.

She also remembered fun activities in fifth grade and learning about space that year.

“You assigned me the planet Jupiter and since then it has always been my favorite planet and it has made me become fascinated with space itself,” she wrote.

“Thank you for everything you have taught me and helping me fight through my challenges and understanding that I needed more help than others,” Juda’s letter concluded. “You have helped me gain confidence in myself and the work that I put into school.”

Kilp said she was humbled and delighted by Juda’s letter, which reminded her why she chose to become a teacher.

“At the end of the day, we are making an impact,” she said. “We are changing lives, maybe one small step at a time.”

Border got the idea for the thank-you letters from an initiative started by the student government association at Freedom High School in south Orange, where he was principal.

The association urged 12th graders to write thank-you letters to Freedom teachers as part of their end-of-high-school activities.

Border noticed many teachers had those letters framed and hung on their classroom walls, obviously touched by what students wrote.

When he became the administrator overseeing all the district’s high schools, Border said he learned other high schools had similar programs and decided to do a districtwide one.

“It’s a favorite event for me,” Border said. “What a great way to celebrate graduation as a K-12 experience.”