Sometimes it does not add up.

You take what the Giants did on Sunday, stack up so much of the good and it seems as if the pile would be high enough to reach to a victory.

In the second half alone, there was an 80-yard touchdown pass from Tyrod Taylor to Darius Slayton and a 94-yard punt return/escape job by Gunner Olszewski for another touchdown.

Two huge, game-turning plays, the likes of which the Giants customarily do not make.

“I’m sure the statistics would lean in your favor, normally,’’ Slayton said.

The problem is, “normally’’ around the Giants this season is shrouded in failure.

And so, they can intercept Matthew Stafford twice (both by safety Dane Belton) and force three turnovers, they can come roaring back from a 20-10 deficit and sack Stafford three times in the second half and they can put themselves in a position where winning is more likely than losing.

And then they lose.

“Wins don’t just occur or fall in your lap,’’ tight end Darren Waller said. “We had opportunities to make it happen and we don’t take advantage of those opportunities you end up with the ‘L.’ ’’

Yup, they end up with the ‘L.’

The Giants did not have anything to play for on New Year’s Eve and yet they exchanged blow after blow with the Rams.

They had a chance to win it, but they put on display with some questionable play-calling in the closing seconds in a 26-25 loss at MetLife Stadium.

Mason Crosby, the recently-acquired 39-year old kicker, was wide left and also short on a 54-yard field goal attempt with 30 seconds remaining to add to the misery the Giants need to leave behind as the new year rolls in.

“I mean there’s plays that we had, mistakes we’ve got to overcome and, everybody, we can just do a better job, starting with me,’’ coach Brian Daboll said. “There were so many opportunities throughout that game that we just came up a little bit short on.’’

The Giants were down 26-19 when Olszewski escaped a sure tackle and sprinted away on his highlight punt return with 3:27 remaining.

That cut the deficit to 26-25 and Daboll was content to tie the game, sending Crosby out for the extra point kick.

But the Rams were called for encroachment on the play and Daboll switched up, opting to go for two from the 1-yard line, now trying to take the lead.

“Liked the call we had and just came up a little short,’’ Daboll said.

Taylor took the snap, rolled to his right and could have run into the end zone.

He also had Saquon Barkley to his right and could have flipped the ball to Barkley for the conversion.

Taylor, indecisive, short-armed the toss, though, and it sailed behind Barkey and to the turf.

“Saquon was open,’’ Taylor said. “Was kind of caught in between running it and throwing it and didn’t do either one of them, but yeah, I got to be better. It’s a routine throw, something I’ve hit plenty of times before.’’

The Giants were out of time outs and got the ball back with 1:08 remaining on their 35-yard line after Isaiah Simmons sacked Stafford on third down.

On first down, Taylor hit Barkley over the middle with room to run, but Barkley dropped the ball.

“A simple option route, I’ve been asking for all year and I make a good read and thinking of taking it to the house instead of securing the catch,’’ Barkley said.

Taylor scrambled for 31 yards to the Rams’ 34-yard line and then spiked the ball to stop the clock with 42 seconds left.

At that point, the best the Giants had was a 52-yard field goal for Crosby, the former Packers’ career scoring leader who was out of the league before the Giants signed him before Christmas to fill a void at the position.

For some reason, the Giants then ran a draw play to Barkley, which lost two yards.

The Giants could not stop the clock but they caught a break when the Rams called a time out with 37 seconds remaining.

Why a draw play there, as it certainly appeared the Giants needed several more yards to get into comfortable range for Crosby on a windy day when Crosby earlier missed an extra point and Rams kicker Lucas Havrisik missed two of them?

Offensive coordinator Mike Kafka calls the plays on offense, but Daboll can veto and change any of them.

“Yeah, I’d just like to have the play back,’’ Daboll said.

Taylor on third down threw a pass into the turf in the general vicinity of Wan’Dale Robinson.

Crosby then was not close on the long-range 54-yard attempt.

“Obviously you hope you creep inside that 50-yard kick,’’ Crosby said. “I felt like we were well inside that range there. Needed to hit it on that right side of the upright with how that wind was blowing, especially once you get out that far, it’s going to move it a little bit more.’’

At least the Giants (5-11) gave the fans spread out among the many empty gray seats an entertaining game.

They are staggering to the finish line, losers of three consecutive games as they mercifully leave behind this miserable season with a Week 18 home game with the Eagles.

The Rams (9-7) extended their winning streak to three games and won for the sixth time in their last seven games.

Taylor, Daboll’s choice as the starting quarterback over rookie Tommy DeVito, got the Giants within 20-16 with an 80-yard howitzer to Slayton.

Crosby’s field goal made it 20-19 early in the fourth quarter.

It was 26-19 after Williams scored on a 28-yard run.

Olszewski pulled the Giants within a point with his punt return and then, well, then the Giants reverted to what they have been this season.

“Yeah, I do think we should have won the game,’’ Slayton said. “But unfortunately we didn’t.’’