Retiree Mark Grashow was visiting a high school in northern Zimbabwe 18 years ago when a teacher showed him a battered edition of “Romeo and Juliet,” which no students were allowed to touch or read when they studied Shakespeare because it was his only copy.

Later that same day, Grashow gave the teacher 50 copies of the play. “I call him over and I say, ‘This is for you,’” he recalled. “He opens up the box and just starts crying. He cries and cries and cries.”

“It touched me to my soul,” said Grashow, now 79. “I saw how important it was to him that all of a sudden, he could give out the books and kids could read them on their own.”

Having retired in 2001 from teaching math at Abraham Lincoln HS in Brooklyn, Grashow was in Zimbabwe to deliver one of the 40-foot containers of books, supplies, sports equipment and furniture that the nonprofit he started, the U.S.-Africa Children’s Fellowship (USACF), routinely ships to rural schools on the continent. He and his late wife, Sheri Saltzberg, co-founded the group in 2003, two years after he retired with 33 years of service.

Grashow first learned about the needs of rural schools in Zimbabwe when he and Saltzberg visited the country after attending a wedding in nearby Zambia. Grashow knew from his years teaching at Lincoln HS, where he was a longtime Key Club adviser, swim coach and chapter leader, that New York City public schools routinely discard furniture, books and other supplies, and he got to work.

What began as a project to help three schools yielded enough supplies for 35 schools in Zimbabwe after about a year, Grashow said. As requests for help have risen, USACF has expanded to help educators and students in Ghana, Nigeria, Sierra Leone, Somaliland, South Africa, Tanzania and Uganda, as well as Jordan, Pakistan and Yemen in the Middle East. To date, the nonprofit has shipped 69 40-foot containers full of donated goods to more than 1,000 rural schools, he said.

In Sierra Leone, USACF built a learning center that includes a tailoring and crafts center where adults are educated in trades. The center is dedicated to Saltzberg, who was an avid quilter. It also includes an educational technology center and two libraries, which have trained teachers and librarians. The center has distributed tens of thousands of books to students and houses a digital library that is part of the Bridge Project, an initiative by USACF to narrow the digital divide. At that site and others in Zimbabwe, Nigeria and other African countries, computers loaded with books, videos, courses and other resources are available to dozens of users at a time through Wi-Fi hotspots.

A sister school initiative will pair 17 Sierra Leonean schools with 17 New York City schools for learning partnerships, said Grashow.

He says his charitable work is guided by the same philosophy that he once impressed upon his students. “I taught the kids to be empowered, not just to do what I say,” he said. “To look around them and see what the needs were in their communities.”