When a modernized Springfield Elementary has a technical meltdown, Lisa transforms it into a Waldorf school. Meanwhile, Groundskeeper Willie becomes the coach of the mathletes. When Lisa and the other kids on the Springfield Elementary Mathlympics Team compete against Waverly Hills Elementary, they instantly get help from a natural genius who uses ancient techniques to compute geometric figures and helps the Mathletes.
The Springfield Elementary School Math team is competing against Waverly Hills Elementary's Math team, in an event organized by Benjamin, Doug and Gary. Lisa shouts that their poor school will surprise them all, which they do...by scoring no points at all. This makes her crestfallen, because Waverly Hills Elementary is much wealthier than Springfield Elementary. Observing Lisa's sadness, the nerds choose to modernize Springfield Elementary School by giving each student a tablet connected to a school network, replacing the blackboards with a giant touch screen device and even making a 3D printing lab.
Since, all books are now digital, Principal Skinner plans to burn the "old" paper books. But a meltdown in the server breaks every single digital device in the school. As all the paper books were destroyed, the teachers have nothing they can use to teach the students. Miss Hoover shows a movie in her cellphone, but Lisa can't see it because other students are blocking her view. Lisa looks out the window and sees Groundskeeper Willie using a rope with some equally spaced knots to measure some grass patches. This gives Lisa the idea to turn the school into a Waldorf School, based on hands-on activities and creative play.
All the kids like the new system, and Willie is promoted to math team coach. While teaching the math team, Willie sees that Superintendent Chalmers is abusing his services and tries to chase him down. During the chase, Bart throws an egg which hits Chalmers in the head, causing his car to crash into a tree. Surprised by Bart's capacity of calculating angles, Willie invites Bart to become the new math team captain. Later, the Waverly Hills Elementary and Springfield Elementary Math teams have a rematch, but Bart didn't know there would be math (even with Lisa stating there would be nothing but math). The new score is more balanced (29-29), even with Bart answering some questions wrong, but none of the contestants understand the answer to the last question: in a M shaped figure, the competitors have to draw three straight lines to form nine non-overlapping triangles. That's when Bart remembers the "M" shaped hair in Homer's head and finds out the solution to the problem, thus leading the Springfield Elementary's Math Team to win the competition.
The episode received very negative reviews. Many critics and viewers have said that the "Rick and Morty"-themed couch gag was better than the actual episode itself.
Dennis Perkins of The A.V. Club gave the episode a D, saying "as the final act of "Mathlete's Feat," the final episode of the 26th season of The Simpsons went to commercial. I was genuinely pissed at how disjointed, lazy, and downright lousy this season finale was."