# Math professor teaches street fighting at MIT

When in doubt, applying street fighting tactics in the classroom can help students learn, says Dr. Sanjoy Mahajan.

Street fighting and self-defense require quick thinking and an ability to “shoot first and ask questions later.” These ninja skills also apply to students in Dr. Sanjoy Mahajan’s class based on his book, “Street-Fighting Mathematics.”

For his class, available to MIT and Massive Open Online Courses students with basic physics and algebra comprehension, Mahajan says he doesn’t want his students to “wait for the perfect kick to come” — he encourages them to just go for it.

The lessons seek to rid students of math anxieties by emphasizing the art of problem-solving without doing an exact, lengthy calculation. “They think, ‘If I don’t get this one right answer, I have nothing,’” he says. The answer itself isn’t the end-all, be-all though. That’s because in his class, a grade is not based on correct or incorrect answers; instead, it’s all about whether they’ve made a decent effort to find the answer.

By showing students an equation as they stare at various symbols in fear, he tells them not to worry, since the answer will be found differently from how they expect it to be anyhow. “The paranoia will freeze them up and just like in a street fight, they’ll get slaughtered.” In order to become liberated, he focuses on action in doing something reasonable and reacting without overthinking a solution — in other words, estimating.

The class challenges the idea that math is supposed to be exact, as students toss away the notion of perfection and right and wrong. To drive home the ninja math technique, he often uses Navier-Stokes equations, considered some of the most complex math equations out there. He says it literally takes years to solve these problems, but “to hell with that, that’s not a street-fighting approach.” With a long, arduous approach, he says problems will not be solved and suggests the street-fighting approach as a way to make progress.

Students inevitably apply the ninja method to other classes as well, Mahajan points out. Approximating helps them simplify, he explains: “When the going gets tough, lower your standards.”

Mahajan used the technique to learn German, for example. The language has endings with seven different forms of the word “the.” Instead of figuring out the proper word endings, the professor went with the most common one. “I was willing to approximate and not get ‘paralysis by analysis,’” he says. Coupled with approximating by slurring the ends of words, locals understood Mahajan based on what their ear was trained to hear. It turns out that the street fighting technique works in German, too.

News
Entertainment
Sports
Lifestyle
National

Bitcoin entrepreneur Charlie Shrem has reached a plea deal to resolve U.S. charges that he engaged in a scheme to sell over \$1 million of…

International

#### China's army changes tactics to prepare for war…

Chinese President Xi Jinping has said China will spur military innovation and called on the army to create a new strategy for "information warfare" as…

National

#### California passes 'yes-means-yes' campus sexual assault bill

Californian lawmakers passed a law on Thursday requiring universities to adopt "affirmative consent" language in their definitions of consensual sex, part of a nationwide drive to curb sexual assault on…

National

#### Syrian refugees top 3 million, half of all…

By Stephanie NebehayGENEVA (Reuters) - Three million Syrian refugees will have registered in neighboring countries as of Friday, but many remain trapped by the advance…

Gossip

#### Joan Rivers on life support: Report

TMZ reports that comedian Joan Rivers has been placed on life support, "completely reliant on machines to stay alive." Rivers has been hospitalized since she…

Movies

#### What's new on Netflix in September

September has a supernatural theme for Netflix. UFO "documentaries" and the survivalist reality series "Doomsday Preppers" are among the new series coming to the online…

Going Out

#### 'Friends' coffeehouse Central Perk coming to NYC —…

"Friends" is coming back for a one-off special: "The One with the Free Coffee." Warner Bros. is bringing a pop-up replica of Central Perk, the…

Movies

#### Interview: 'As Above, So Below' directors: 5 ways…

The fraternal directors of the found footage horror "As Above, So Below" dish on the best ways to frighten the bejesus out of audiences.

NFL

#### 3 things we learned in the Giants preseason…

The final score didn’t matter — a 16-13 win by the Giants — but it would’ve been nice to finally see Big Blue’s new-look offense get on track.

NFL

#### NFL Power Rankings: Seahawks, Broncos, Patriots, 49ers start…

NFL Power Rankings: Seahawks, Broncos, Patriots start at top

U.S. Soccer

#### 5 facts about new England captain Wayne Rooney

Manchester United striker Wayne Rooney was named as the new England captain by coach Roy Hodgson on Thursday.

NFL

#### Jets vs. Eagles: 3 things to watch

A win on Thursday night at the Eagles would give the Jets a 3-1 record and just their second winning preseason under head coach Rex Ryan.

Wellbeing

#### VIDEO: Still not wearing sunscreen? You will after…

Sunscreen is possibly the most often repeated - and ignored - piece of skincare advice. But Thomas Leveritt took a different tactic. With a short…

Food

#### Twitter used to track down sources of food…

When Chicago health officials saw Twitter users complaining about local food poisoning episodes, they reached out on Twitter to those users and often ended up…

Style

#### Trend: White hot on the 2014 Emmy's red…

White was one of the big trends on the Emmy's red carpet.

Food

#### Recipe: Samuel Adams beer-marinated grilled shrimp

Summer calls for two things: a cold beer and light food. Sam Adams' Latitude 48 IPA fairly bursts with citrus notes, making it an ideal marinade…