The questions came one after another to Ben McAdoo, the first-year Giants offensive coordinator, all essentially seeking the same information. How has Tom Coughlin adapted to this new way of doing things? How has he picked it all up? Has he resisted any of the many changes? Can you indeed teach an old dog some new tricks?

That last one got to McAdoo.

“What is the title of this story?’’ McAdoo asked.

Well, Ben, since you asked, here goes: Coughlin Makes Most Drastic Adjustment of his Career.

Every successful coach is known for something, rises through the ranks on the strength of a particular area of expertise. Every step of the way, it’s been offense for Coughlin. Working with backs, receivers, quarterbacks, serving as coordinator, he’s done it all. As a head coach, he ran HIS offense. It’s his background, his acquired knowledge, his beliefs, his football philosophy. His offense is his baby.

“That’s fair to say, yes,’’ Coughlin said.

Until now.

At the age of 68, in his 20th year as an NFL head coach, Coughlin has given up his offense, scrapped it and replaced it with a new approach brought in from, of all places, historic Green Bay, delivered by a 37-year old who had never before coordinated anything, never before created his own offense. When Coughlin became the first head coach of the Jaguars in 1994, McAdoo was a part of the Homer-Center High School District 6 championship team in Homer City, Pa.

Every smart coach adapts, and Coughlin’s personal makeover after the 2006 season was startling as he replaced his stern image with a more caring and in many ways more vulnerable persona. His players finally believed the venerable coach cared about them, and two Super Bowl victories later, Coughlin’s kinder, gentler touch remains a transformation deserving of Giants legend.

This is more dramatic because it cuts to the heart of Coughlin’s football identity. This season, with the offense “broken’’ in the terse assessment of co-owner John Mara, Coughlin had to make the football right and to so do he had to seek a divorce from his offense, severing a relationship for the sake of a younger model.

After a rough start — predictable, really, given the enormity of the changes — the Giants are 3-2, averaging 26.6 points a game and the hoped-for revitalization of Eli Manning has him humming along with career-highs in completion percentage and quarterback rating heading into Sunday’s showdown in Philadelphia.

In revealing interviews with The Post, Coughlin and McAdoo shed some light on the steps taken by a veteran coach willingly giving up his offense to allow the younger assistant to take control.

“The decision to change and change radically, to be honest with you, was made in the best interest of our team,’’ Coughlin said. “It was made in the best interest of our quarterback, it was made in the best interest in stimulating and inspiring at a point, quite frankly, I thought the timing was right and it could be accomplished.’’

The timing was right in that it was clear ownership demanded change, Coughlin knew there would be tremendous upheaval on the roster and longtime offensive coordinator Kevin Gilbride, perhaps seeing the writing on the wall, retired.

“I think of the number of years, when Kevin became the coordinator, of the productivity of the offense, I don’t think it was anything wrong with the on-paper offense, ‘’ Coughlin said. “I just felt the change was necessary.’’

The change could have been accomplished by bringing in a new individual and not an entirely new philosophy, as Coughlin could have picked Mike Sullivan, a former Giants assistant (and former Buccaneers offensive coordinator). Instead, Coughlin admits he opted for a “radical adjustment’’ and hired a complete stranger, knowing full well McAdoo was weaned on the West Coast offense with the Packers. This was going to be nothing like the offense Coughlin took with him from his days as receivers coach for Bill Parcells and installed at Boston College in 1991, installed in Jacksonville in 1995 and installed with the Giants in 2004.

Coughlin took a look at himself, a sagging, regressing Manning, the way the NFL was operating with all the up-tempo, the no-huddle, the spread offenses, quick reads and throws, and decided a new direction was the best direction to follow.

“Stimulate the veteran players who remain here and in particular to capture the imagination, the interest and the inspiration of our quarterback,’’ he said. “I thought this would be the move would give us the best chance to accomplish all of the above.’’

McAdoo was happy in Green Bay working for Mike McCarthy and would not have come if he was told to run someone else’s offense.

“For me to pick my family up and move them after eight, nine years in one location the opportunity had to be too good to be true,’’ McAdoo said.

He had great respect for Coughlin and Manning, who “broke my heart … twice’’ in the playoffs following the 2007 and 2011 seasons, and was assured his offense would be the one put into action.

“To be able to sit down and talk about how we wanted to run things and having a plan for that before we even got to taking the job or not taking the job, I felt great about it,’’ McAdoo said.

The quickest way to get a cringe out of McAdoo is to refer to what’s going on as “the Ben McAdoo offense’’ even though that’s essentially what it is. He arrived with what he calls “a blank piece of paper’’ and, with a revamped offensive staff and Coughlin went about the tedious task of putting together a playbook, page by page. “It’s OUR offense, no question,’’ McAdoo said.

It is far more foreign than it is familiar to the Giants.

“It’s different for a lot of guys who’ve been here,’’ McAdoo acknowledged. “It’s different primarily for the quarterback. The way he thinks about plays may be different than the way he thought about ’em in the past. We put on a lot on Eli.’’

Coughlin has his hand in everything — he’s not one of those “You deal with your side of the ball’’ head coaches — and he had to hit the books in order to keep up with what McAdoo was teaching.

“There’s a lot of newness,’’ McAdoo said. “The challenge is we used to call it this and now it’s that.’’

Coughlin spent many of his springtime mornings studying the new terminology and asking “a million questions’’ in order to get a grasp of McAdoo’s system. It was back to school for the old coach.

“This is like a foreign language, what you have to do is try to understand what the meaning is so that you can compare it to the old terminology,’’ Coughlin said.

The old system was more streamlined in the verbiage, which was Coughlin’s preference.

“There’s a lot of descriptive terms and you have each position basically being told what to do on every play,’’ Coughlin said. “Ben wanted to do this from Day 1.’’

That means Coughlin had to learn to speak McAdoo, without the Western Pennsylvania dialect.

“This is his offense too, this is our offense,’’ McAdoo said. “To be able to accomplish what he’s accomplished in this business I mean, it says a lot,. The league has changed so much since he’s been in it. You always adapt and you always improve and you always change.’’

With that, McAdoo added, “This may be a little more drastic than it has been in the past.’’

More drastic than any change Coughlin has ever made to his football operation.

“I’ve said for years: It’s not about me,’’ Coughlin said. “If I don’t have an ego than I certainly expect all those around me to follow my pattern. The idea of trying to serve in the best interest of everyone, it’s not about me, it’s not about my ego, it’s not about stroking my personality. It’s about doing what’s best for the New York Giants.’’