We’re taught that one plus one equals two. This equation holds up pretty well — until you become a parent of twins. “It’s not double the work,” says Dave Novak, a local father of twins. “It’s exponential.”

I know what he’s talking about. About six months ago, my wife, Laura, and I became parents of twin girls, Lucy and Stella. They’re our first children, and they’re keeping us busier than we’ve ever been.

So I agree with Novak’s assessment of the exponential workload that twins create, but I also sense hidden advantages to raising them. For one thing, it’s difficult to “spoil” a twin. There isn’t time. Just keeping them fed is like a high-stakes game of Whac-a-Mole. And, so far, our twins are on the same developmental schedule. This means the whining produced by teething pain — which in our home calls to mind killer bees straining to buzz in harmony — is something we’ll have to bear for only one stretch. Yet we still get to have two kids.

Moreover, according to twin lore, as our girls grow, they’ll cherish each other’s constancy as friends and playmates. I look forward to that. Right now, when they’re within reach of each other, they pull hair, yank ears and try to stuff the other twin, whole, into their mouths.

But I’m probably getting ahead of myself. My daughters are infants. We set them down; they stay put. They cry; we feed them. They cry but don’t want to eat; we tuck them in for a nap. They’re healthy, and they’re good sleepers, so the “fog of twins” the baby books got me all worked up about hasn’t rolled in too thickly … yet. Conversations with parents of older twins, however, reveal that the experience grows in complexity as the pair develop — especially, as Novak notes, when their little legs start carrying them in opposite directions.

For him, that time coincided with his divorce, when twins Max and Lily were about 3. On single-parent outings with them and son Dylan, older by six years, Novak sometimes literally had to chase both twins down and haul them back to the pack. Novak’s ex, Kelly Wells, remembers that period in similar terms: as the era of pushing two grocery carts when she did her food shopping. Novak calls it the most challenging phase of parenting twins so far — worse than the years during which he and Wells failed to get decent sleep.

The situation was even more dire, in some ways, for Sue Donahue. Although she isn’t a single parent, when twins Ian and Mia came along, she and husband Steve already had 20-month-old Amy and 3-year-old Kaitlin at home.

Those numbers are staggering to many parents. “People are always amazed, and they can’t think about how they would manage in that situation,” Donahue says. “What they don’t realize is, you just figure it out. It becomes your family, and you just work it out.” In Donahue’s case, as in ours, “working it out” started with getting a bigger car. For us, a bigger house came next. The Costco membership was a no-brainer.

Actually, the first major challenge that soon-to-be parents of twins face is getting their minds around the idea of twins. Artist and mom Lisa Lillibridge describes a “mourning” period following the news that she and husband Jeff Govoni were expecting two. Their son, Ellis, was 3 at the time, and other household stressors were kicking in hard. They’d planned on having another kid — one. Suddenly, they had to scrap their idealized family portrait. “Four is actually a nice, manageable number” of family members, Lillibridge says, but five is a game changer. Of course she and Govoni adore their twins, Willa and Lucy, now 10. Before their birth, though, Govoni remembers feeling like he and his spouse were heading “back into baby prison.”

Wells had the opposite reaction to the news of her twins. Already mother to a 6-year-old, she knew that “having two children would not feel like enough children for me,” she says. So she was thrilled to find out she was carrying twins. “I thought, Wow, I get to have three. It felt like a real gift to me.”

Laura and I were initially blown away by our own news. After a few days, we accepted the idea of two babies, and then we embraced it. We also welcomed the chance to raise a bigger family than we, both in our early forties, had thought possible. The greater medical risks associated with double births raised some concern, but each doctor’s visit allayed our fears. Today, our ignorance of the relative ease of raising a singleton may partly explain why we find so much bliss in caring for Lucy and Stella.

Admittedly, I’d be struggling to find time to write these words if we didn’t have professional childcare help. When you consider the expense of day care doubled, a nanny suddenly seems cost effective instead of extravagant. Laura and I were lucky to find Heather Reynolds, a nanny experienced in caring for “multiples” who has a knack for getting our girls to eat, sleep and smile. That Reynolds is also a young mother and a former firefighter offers Laura and me additional reassurance while we’re at work.

Lillibridge describes her family’s helper, Joanne Flynn, as her kids’ “Burlington grandmother.” Flynn remains in the family picture, even though her twin charges are now tweens. “We couldn’t have done the twin thing without her,” Lillibridge acknowledges. “Traditions were established with her that will keep going a long time.”

Whether or not a parent of twins has the resources or inclination to pay for childcare, additional help must come from somewhere, period. Our girls’ pediatrician, Dr. John Long, observes that, by necessity, fathers are generally more involved in twin parenting than in singleton parenting. And, he points out, a high degree of parental involvement correlates with well-functioning families. Moreover, Long says, family members tend to take a shared interest in the unique interactions of twins.

Kelly Wells sees similar results in her job as an administrator and preschool teacher with the Visiting Nurse Association Family Room. “When the father is involved in parenting the twins,” she says, “there’s a lower level of stress in the family, especially in the early years.” Wells also advocates being open to help from outside the family, whether that’s a door held by a stranger or a friend keeping an eye on one twin while you chase down the other. “I learned how to be really grateful for those moments when people were willing to extend a small amount of help,” she says. “For me, that was huge.”

“Huge” also describes the interest the public shows in twins. Try getting anywhere in a hurry behind your double stroller. And the compliments, questions — or expressions of sympathy — while well intended, further delay a bleary-eyed parent from getting home with that coveted pound of coffee.

The parents of twins, and the twins themselves, may eventually tire of being a “public science experiment,” as Lillibridge puts it. Yet the private benefits of being a pair are probably worth it. For one thing, that famous twin bond guarantees each a friend for life. This irrevocable relationship, in turn, teaches its own lessons. “I think the greatest advantage of ‘twinness’ is that they’re socially sophisticated,” Lillibridge says. “If there’s a problem, you have to solve it, because this is not a friend that you can end it with.”

Wells agrees: “What they’re learning from each other,” she says, “is so important for children, especially in the early ages: how to live and be together.”

But parents of twins should strive to ensure the two aren’t always lumped together as a unit. “They were always referred to as ‘the twins,’ and we really tried hard not to reinforce that,” Bob Osmond says of his twin girls, Abigail and Claire, born when son Emerson was almost 3. For starters, Osmond and wife Marina Ecklund did not dress their daughters in matching outfits. In preschool, they put the girls in separate classes. “We know that to be very helpful,” Osmond says. He credits this strategy with helping their girls, now 6, cultivate their own identities. Maybe this way they don’t get sick of each other — because, he adds, “they almost never fight.”

Respecting twins’ differences is one thing, but giving them individual attention remains a challenge. “It’s much harder to find time individually with them,” Novak says, “than it is to separate my [older] son from them.” He, Govoni and Osmond all mention deliberate parenting measures they and their partners take to single out their children for one-on-one time.

Still, structure seems to be key to keeping twins in line — and enabling parents to survive. Govoni and Lillibridge employ parenting strategies that draw on some old-school moves: They teach the kids the meaning of “no,” maintain sacrosanct bedtime rituals and keep in mind that “if everyone’s alive at the end of the day, it’s a successful day,” as Lillibridge wryly comments.

An important goal is meeting the children’s needs without sacrificing the parents’. The birth of Lillibridge’s twins inspired her to find an art studio outside the house. “I’ve probably produced more because of having the need to find time for myself,” she says. She calls the move both “self-preservation” and “a really good model for my daughters. I don’t think just logging the time [with them] naturally makes that a better model,” says Lillibridge. “I want to foster a lot of other relationships that make them feel safe. I don’t want to be everything to them.”

Govoni takes a similarly holistic view of parenting. When he and Lillibridge are strict, he says, “It’s not because it’s good for the kids but because it’s good for the family.” Their approach seems to be working. It has allowed Govoni to protect what he identifies as the most important bond in the equation: his connection to his wife. Being the parents of twins “could’ve pushed Lisa and me apart,” he says, “but it has brought us closer together, because no one knows what we’ve been through but each other.”

I suppose all parents, not just the parents of twins, subscribe to the uniqueness of their experience. Still, I’ll venture that couples expecting twins ponder one question more deeply: Are we going to be able to do this?

This question kept me up at night — even before my daughters started doing so. Anticipating their arrival was like bracing for an alien invasion. We knew they were coming. We’d seen their spectral images, heard their sonic pulsations in the murky beyond. We just weren’t sure what they’d demand from us.

As it turns out, they demand much, in great variety, in patterns that scramble as soon as we’ve figured them out. I remind myself often — say, when I’m changing one of the several thousand diapers our girls will go through in their first year — that we invited them here. Attending to them can be trying. But even the most fatigued parents of twins confirm what Laura and I anticipated from the day we learned we were going to join their ranks: that raising twins produces incalculable rewards. Not double rewards. Exponential.