WEYMOUTH — Millennials venturing out into the world may know how to add, subtract, and tweet, but do they know those truly essential skills of adulthood, like how to shake hands, sew back popped buttons, and do laundry without turning white socks pink?

The answer is a resounding “no,’’ according to those offering instruction in “adulting’’ — the newly coined word for learning how to be a grown-up.

Adulting classes are popping up from Maine to Texas to Oregon to, closer to home, Weymouth, where Adulting 101 at the Tufts Library consists of eight how-to classes designed to ease teens and young adults into full-scale adulthood. The free monthly sessions run through May and are open to people ages 16 to 25 from all communities.

The series kicked off in the fall with How to Avoid Offending: Etiquette 101, and segued into How To Avoid Starvation: Food 101. Other basics on the agenda include How to Avoid Living in Your Parents’ Basement Forever: Home 101; How to Avoid a Meltdown: Stress 101; and the ever-useful How to Avoid Unemployment: Work 101.

In a letter sent to parents and teachers to recruit participants, reference librarian Kristy Lockhart wrote that the intention of the program was to help bridge the “soft skills gap’’ found in recent high school and college students.

“Increasingly, surveys find that emerging adults are feeling overwhelmed and underprepared for gaining employment and living independently from their families,’’ she wrote. “Soft skills training can help a new adult succeed in life no matter what they are doing. Our hope is that this series will give young people a space where they can ask questions, assuage their anxieties, and help them feel more prepared to face the post-high school or post-college world.’’

Not everyone is a fan of adulting education, though.

Lenore Skenazy, author of “Free-Range Kids, How to Raise Safe, Self-Reliant Children (Without Going Nuts with Worry),’’ said the trend is symptomatic of the helicopter parenting that she believes is stunting young people’s ability to grow up by themselves.

“It’s hard for kids to learn any kind of problem-solving because we’re always there, solving their problems,’’ Skenazy said in an e-mail. “Kids, like the rest of us, learn by seeing and doing. When adults step back, kids step up.

“Ironically, adulting classes sound like the problem that got us here: not trusting any common sense or resilience to kick in. Once again we take kids by the hand, when what they really need is for us to let go a little,’’ she said.

In Weymouth, Lockhart said the reaction from parents has been overwhelmingly positive, although it’s been tougher selling teens on the idea.

“Advertising it in a way that doesn’t seem that they have to admit they don’t know something has been a challenge,’’ she said.

So far, the classes have attracted a mix of ages and aptitudes, and an encouraging lack of embarrassment about being there, Lockhart said.

“We get some kids who are being encouraged by their parents because they need some extra help, and there are some kids who really seem super-confident and like they could win at life tomorrow,’’ she said.

A group of six, ranging in age from 16 to 22, attended the first class on etiquette and gamely practiced shaking hands — up, down, and done — and learned to subtly dry sweaty palms on the side of their shirt or pants before engaging. Another takeaway: When encountering the “limp fish’’ handshake, take it in two hands and gently support it.

From there, the group moved on to the finer points of introductions — if there’s more than one person to introduce, always introduce the older or more powerful one first — table settings, and protocol.

“The whole idea of etiquette is that you know the rules and therefore are comfortable in situations,’’ explained instructor Cathy Torrey, chairwoman of the Weymouth Library Board of Trustees. “Etiquette is trying to keep everyone comfortable and from being embarrassed.’’

After a break for pizza, the group moved on to learning how to cut and serve a round cake without ever touching it — an adult skill if there ever was one.

The second session, on avoiding starvation, covered basic nutrition and cooking, focusing on how to feed oneself in a dorm room. The highlight of the evening was a demonstration of how to make quesadillas with an iron and tin foil.

“What surprised us was there were a couple of kids who cooked quite a bit at home,’’ Lockhart said. “One of the boys talked about a salad he’d made with kale and a soft-boiled egg.’’

Myra West, a junior at Weymouth High School, heard about the program through her mother, and found the session she attended “fun and pretty informational.’’ She’s planning to go to more.

Lockhart said young adults can come to as many, or as few, of the sessions as they want. She also said the program was inspired by Adulting 101 classes sponsored by libraries on the West Coast.

“This is a big topic for librarians’’ — relieving “stress and anxiety for young people,’’ she said.

Carnegie Library in Pittsburgh offers a similar series, with the pitch: “On your own and clueless? No need to call Mom. Come learn here how to be an adult.’’

Variations on the theme are available in North Bend, Ore.; Pflugerville, Texas; Lafayette, La.; and Cape Girardeau, Mo.

In Portland, Maine, the Adulting School garnered lots of buzz last year when it combined happy hours and similar events with classes in such skills as how to change a flat tire and how to fold a fitted sheet.

The school has renamed itself the Adulting Collective — to make it sound more fun and less academic, according to cofounder Kate Brunelle — and is going strong, sharing knowledge that teens used to learn from their parents or home economics classes.

One example of a recent Adulting Collective offering: how to cut fruit, featuring mangos and a sharp knife.

Don’t try this at home, young nonadults.

Johanna Seltz can be reached at seltzjohanna@gmail.com.