CARY - Mary Ellington knew it was time to learn more about computers when her 9-year-old grandson asked for her e-mail address.

She didn't have one.

"I felt so left out of the modern world," said Ellington, 74.

So after months of nagging from family and friends, she enrolled in Computing for Beginners, a class at the Cary Senior Center.

Ellington is one of a growing number of Cary seniors trading a pen for a keyboard.

SeniorNet, a nonprofit organization that helps seniors learn computing basics, organizes the courses at the senior center.

Courses, which are offered to adults who are 50 or older, help students learn about digital photography, Google, social media and basic computer organization methods.

This year, a record number of seniors are expected to participate in SeniorNet courses in Cary.

Through Wednesday, about 669 seniors had completed or signed up for a course this year, according to the town.

The total, a five-year high, could grow.

Registration is ongoing.

The next set of classes starts Sept. 13.

"We start by teaching people how to use a mouse," said Darryl Mills, a SeniorNet coach.

Mills is part of a 40-member team that volunteers to teach classes.

He says instructors urge seniors to practice using a mouse by playing computer card games in their spare time.

"There's only so much we can handle at once," Joe Gelm, the SeniorNet program coordinator, said.

Gelm says mastering technology can be useful for seniors who become less mobile but who don't want to be socially handcuffed by a lack of digital savvy.

The high popularity of SeniorNet classes has left many on waiting lists each of the past five years, says Jody Jameson, senior center supervisor.

"Technology is expanding at such a rate that, to people who haven't ever touched a computer, it can be scary," she said.

Rhonda Mitchell, 60, signed up for the beginners' course to learn the basics of using a flash drive.

"I've learned a lot just in the few days I've been here," Mitchell said before a class this month.

Since enrolling in classes this year, she has learned how to clear space on her computer, store photos, and create her own Facebook profile.

Mitchell says one of the most useful tips she learned was how to properly shut down a computer.

"I used to just hold down the button," she said.

She joined Facebook to keep in touch with her 30-year-old son, Micah, in Atlanta.

"He accepted me as his friend about two months ago," Mitchell said. "But after looking through his photos, I told him I might not want to be his friend after all."