Here’s this week’s Smartmom from the Brooklyn Papers:

One day while lunching on a turkey sub at the Subway on Seventh Avenue, Smartmom ran into a mom she knew back when Teen Spirit was in elementary school.

“I haven’t seen you in ages,” Smartmom’s Mom Friend exclaimed. Smartmom put her sandwich down ready to launch into “The School Dialogue.”

Where’s he in high school? How does he get there? Does he like it?

The questions came fast and furious. The curiosity was sincere and unstoppable: an enthusiastic conversation among friends who’d lost touch.

Beacon. Bay Ridge Prep. F train to the A to Columbus Circle. The R train to Bay Ridge. He likes it. Yeah.

The neighborhood teenagers are strewn about hither and yon. Some go to schools nearby like Murrow, Midwood, or Brooklyn Tech. Others journey to schools in boroughs far away like Stuyvesant, Bronx Science, LaGuardia and Nest.

While many of the teens have managed to stay in touch with the friends they made in middle and elementary school, their moms have, in many cases, lost the connection.

Back in the day, they’d chat during Choice Time, in the school’s backyard while waiting to pick up their boys, during Parents as Reading Partners one Friday morning a month, at the Holiday Craft Fair.

Standing in line at ConnMuffCo, they’d compare homework loads, middle school applications, and learning styles.

It’s almost as if those friendships were site-specific. They thrived because they shared an intense situation during an intense time. When that experience ended, so did the friendship. No effort was made to stay in touch because they never had. They didn’t even know each other’s phone numbers.

At Teen Spirit’s graduation in the sweltering hot auditorium at John Jay, Smartmom shed tears when the class sang “525,600 Minutes,” the song from “Rent.” She cried for this milestone in her son’s life, but also for the friends she’d made that she knew wouldn’t survive a change of venue.

During middle school, Smartmom rarely ventured inside Teen Spirit’s Fifth Avenue public school. Sure, she went to parent-teacher conferences, curriculum night, school plays and concerts. But that was it.

Since he walked to school and came home by himself there were no drop-off or pick-up friendships. There were few opportunities to gather in the kid’s classroom, little time to form even temporary friendships.

Now that Teen Spirit is in high school, Smartmom almost never visits his Bay Ridge private school. And Teen Spirit wants to keep it that way. She doesn’t know the names of more than a few of the kids in his grade. They don’t even take a class picture anymore.

Buddha knows, Teen Spirit guards the identity of his high school friends like a chef’s secret ingredients. And she wouldn’t know their parents from Adam.

This worries Smartmom. What kind of kids is Teen Spirit bonding with? For that matter, what are their parents like?

At Subway, the old mom friends reminisced about the third-grade teacher with the well-deserved reputation for running a tight ship.

“Remember how she drilled them in the multiplication tables?” she said.

Really old school. But a very good teacher she was.

And who can forget the fourth-grade sleep-away trip to the Pocono’s?

“That was the first time my son ever slept away from home,” the Mom Friend remembered.

“It was so quiet when Teen Spirit was away. OSFO really missed him,” Smartmom added.

For the first time in 20 minutes, there was a lull in the conversation.

“Can you believe they’re going to college in less than three years?”

The thought took Smartmom’s breath away. Literally. She felt her anxiety rise. Not because of college essays, SATs, and college trips — but because she can’t imagine life without Teen Spirit on a day-to-day basis.

Silently, the two moms shared the idea that their little boys were turning into men who would one day embark on college and the life beyond.

“I can’t wait to turn his room into a workout space,” the Mom Friend joked.

“Teen Spirit’s room will make a terrific office. I’m counting the days.” Smartmom chimed in.

They didn’t mean it. Not a word. Those rooms would be like shrines, awaiting the time their boys needed to come home. The jokes were a way to deny the fear and confusion. How had their children gotten so old?

For that matter, how had they?