The Mets appeared to forget some valuable grade school lessons on Friday night.

During the top of the sixth inning of the team’s game against the Angels at Citi Field Friday night, the entire team seemed to forget how many outs had been recorded despite all indications that the half-inning was over.

Kodai Senga started the frame by inducing a flyout from Luis Rengifo before issuing a walk to Logan O’Hoppe.

With one out, Senga got Hunter Renfroe to ground to third baseman Jonathan Arauz, who flipped to second for one out before Danny Mendick flipped it over to Pete Alonso to first base for an inning-ending double play.

But the Mets didn’t seem to be in the know.

The team started to throw the ball around the infield as if the inning was continuing.

“Arrauz handling that hard one-hopper with aplomb and starting a 5-4-3 double play to end the inning,” SNY play-by-man Gary Cohen said. “The Mets have no idea how many outs there are.”

It took about 10 seconds or so before the Mets were clued in and started walking off the field.

Senga smiled, whether confused or thinking the wacky situation was funny.

He finished his outing two outs into the seventh, allowing two runs while striking out 10.