Before they can even read, almost a quarter of children in nursery school are learning a skill that even some adults have yet to master: using the Internet.

About 23 percent of children in nursery school -- kids age 3, 4 or 5 -- have gone online, according to the Education Department. By kindergarten, 32 percent have used the Internet, typically under adult supervision.

The numbers underscore a trend in which the largest group of new Internet users are age 2 to 5. At school and at home, children are viewing Web sites with interactive stories and animated lessons that teach letters, numbers and rhymes.

"Young students don't differentiate between the face-to-face world and the Internet world," said Susan Patrick, who oversees technology for the department. "They were born into the age of the Internet. They see it as part of the continuum of the way life is today."

At a preschool age, children need adult help to get online, said Francie Alexander, chief academic officer for children's book publisher Scholastic Inc.

One of their favorite computer activities is writing an e-mail to a grandparent, said Alexander, author of a children's guide to the Internet.

"It's great for letter recognition," she said. "Everybody likes to get mail and little kids don't have great tolerance for waiting. So the whole idea that they can write Grandma and get an e-mail back a half-hour later saying, 'I got your note' -- they love that."

Overall computer use, too, is becoming more common among the youngest learners. Department figures show that two-thirds of nursery-school children and 80 percent of kindergartners have used computers.

At the Arnold & Porter law firm's children's center in Washington, 4- and 5-year-olds have the option to spend time on a computer, working in small groups. They learn basic problem-solving and hand-eye coordination, but the social component of working with classmates on computer exercises is just as important, said Sally D'Italia, director of the center, which the firm offers for its employees.

"It helps them become more relaxed, more adventurous and more willing to take risks as they learn," she said. "With adults, we're still afraid that we're going to blow up the computer. You never know if you're going to push the wrong button and lose all your data."

Virtually all U.S. schools are connected to the Internet, with about one computer for every five students, the government reports. Many older students are often far ahead of their teachers in computer literacy, and they know that their younger siblings are gaining on them.

Educators say such access needs scrutiny.

Beyond blocking inappropriate content, schools must be certain the lessons they choose are based on research and geared to the developmental stage of the children, experts say.

"Kids have a tremendous ability to expand their learning, and a computer is just one tool," said Mark Ginsberg, executive director of the National Association for the Education of Young Children.

Max, 4, of Bethesda, left, and Sarah, 4, of Washington work on a computer at the Arnold & Porter children's center.