When women’s gymnastics overhauled its scoring system ahead of the 2008 Summer Olympics in Beijing, the sport that had once been all about clean execution added a new focus: risk. Eight years later, there’s one gymnast who has mastered the art of execution and whose degrees of difficulty have made her the world’s best: Simone Biles.

The gymnastics world Biles inhabits looks very different than when the “perfect 10” made Nadia Comaneci a household name in 1976. Two scores are now tallied to create an overall score for the gymnast. The “A” score measures the difficulty of the routine and the “B” score deducts points based on mistakes. With final scores ranging from 13 to 15 and medal-winning scores rising above 16. The tougher the routine, the higher the potential score.

There’s an obvious reward for the gymnasts who choose more difficult routines.

During the individual all-around competition at the 2012 London Olympics, the average score for gymnasts choosing a degree of difficulty between 5.5 and 6 was 14.

For those whose degree of difficulty exceeded 6.5, the average score was 15.6.

But the worst score for the tougher routine was 15.1 compared with the best score of 15.2 in the less-difficult routine. In other words: go big or go home.

Because Biles consistently chooses tougher routines, The Post’s Liz Clarke writes that “barring a rare misstep, she’ll be untouchable on vault, floor and beam.”

On the vault she performs the Amanar, which earned her a 6.4 degree of difficulty — it typically carries a difficulty score of 6.3 — and a 9.9 execution score at the 2015 U.S. championships for a total of 16.3 points, narrowly beating out McKayla Maroney’s routine at the 2012 Summer Games (16.2) for highest score all-time under the new scoring format.

And now that it looks like Biles will upgrade her second vault to the Cheng, a move she showed off at the 2016 Pacific Rim Championships, which is usually worth a degree of difficulty of 6.4.

If a back injury doesn’t force Russian Maria Paseka from the Rio Games, she might be the biggest threat to Biles. During the 2012 Games, Paseka — who beat Biles on vault at the 2015 world championships — won bronze with difficulty ratings of 6.5 and 5.6 in her first and second vault, respectively in the final round.

North Korea’s Hong Un Jong, the 2008 Olympic champion and 2014 world champion on vault, could also be a threat. In fact, Biles upgraded her second vault to a Cheng to keep pace with Hong, who used it to beat Biles in previous years. Not to be outdone, Hong has been practicing a move that has never been executed in competition by a female gymnast: the triple-twisting Yurchenko, which is the Amanar plus an extra half twist.

According to NBC’s Julia Fincher, Hong has submitted the triple-twisting Yurchenko at the 2013, 2014 and 2015 world championships, but never performed it in competition. If she can pull it off, not only would it reward her with a 6.8 difficulty rating, higher than Biles’s Amanar, it would become known as the Hong vault.

But the vault is Biles’s weakest event — she took two silver medals and one bronze on vault at the last three world championships — and is the only apparatus on which she didn’t dominate at those competitions.

According to Slate’s Dvora Meyers, Biles “attacks her skills with vigor, especially her dismount series,” on beam, often ending with a dismount so difficult that judges are likely to forgive minor imperfections.

Russia’s Aliya Mustafina, the 2010 world all-around champion, had a more difficult beam and bar routine in the 2016 Russian Cup than Biles did at the P&G Championships, but she was edged by Biles on vault and floor for a higher total difficulty score.

On floor, Biles has no equal. Her signature move, aptly known as “the Biles,” is one that few, if any, gymnasts dare to perform.

She flips backward with a straight body two times, and on the second flip, she does a half turn and she lands forward,” her coach, Aimee Boorman, explained to ABC News. “So she’s going backwards. She’s like arched backwards, and she flips and then starts her second flip. And before she finishes the second flip, she turns her body.”

At the P&G Championship, Biles had a 6.8 difficulty on floor in both the preliminary and final rounds. Her closest competition that day was Aly Raisman with difficulty scores of 6.7 and 6.6, respectively, in the prelims and finals. No other competitor was higher than 6.5, and nine of the 14 women in the event had at least one floor routine with a difficulty rating of less than 6.

In other words, if you want to beat Biles at the Olympics, you have to create one of the most difficult routines you can think of in addition to executing it at an elite level.

Since her international competition debut in 2013 — she didn’t meet the minimum-age requirements for the 2012 Summer Games  — Biles has won 14 medals at the world championships, including 10 golds, and became the first woman since 1974 to win four consecutive all-around titles at U.S. nationals. She is also the first woman to be the all-around world champion three years in a row.

Next up for Biles: hoping to make history as the first woman to win five gold medals in a single Games. And based on the difficulty of her routines, she’s got a good shot.