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Pioneer Press, Jean Pieri, Associated Press
In this photo taken Nov. 16, 2011, Mani Chadaga, a third-grader at Capitol Hill Magnet School, leaves his geometry class with older students and goes to his third grade class in St. Paul, Minn.

ST. PAUL, Minn. — In his first algebra class last year, Mani Chadaga slumped low in his front-row seat and pretended to read his new textbook intently.

Mani could make himself only so inconspicuous: He was, after all, a second-grader in a junior high class at St. Paul's Capitol Hill Gifted and Talented Magnet School.

So he stopped trying.

Soon, he was piping up with solutions to the teacher's questions and standing before his stumped classmates, explaining how he arrived at them. These days, as a third-grader juggling Algebra II and geometry, he kneels in his seat, only a smidgen of his early shyness and all his humility intact.

"I am not the best at anything, so I want to improve at everything," said the 8-year-old.

Mani's parents and teachers are bracing for the task of keeping things interesting for him in the coming years. To Vivek and Julia Chadaga, his story shows how far schools have come in catering to voracious learners like Mani. But it also shows that when restless curiosity and true passion hold sway, age really is just a number.

Mani and his parents can trace the beginnings of his fascination with math to age 2 or 3, when he invented the Number Creatures. He drew pages upon pages of these numbers with faces and personalities, peering out the windows of their futuristic skyscrapers in the galaxy Hexer.

"He created a whole mythology around numbers," Julia said.

A couple of years later, Mani went trick-or-treating dressed as the number 4, baffling the neighbors. By 4, he readily added and subtracted. By 5, he'd mastered the multiplication table.

Kindergarten started with a strange test: He had to count to 10. At that time, he could count to 1,000, and he did - all the time.

"Put away your dishes," his parents would say.

"Don't interrupt me," he replied. "I am counting."

Both Mani's parents are word people, rather than number people: Julia Chadaga teaches Russian at Macalester College. Vivek Chadaga is a freelance editor.

But they, too, were precocious learners, and now they were worried about school. In rural Pennsylvania, one elementary teacher would sit Vivek Chadaga in the back of the classroom with a copy of Reader's Digest. His parents would field calls from other teachers: "He's just bored out of his mind, and we have no idea what to do with him."

The Chadagas wanted Mani to have a more stimulating experience, but it was also important to them that their son spend most of the school day with his peers.

At Capitol Hill, all students take a math test at the start of the school year, which lands roughly half of them in a higher grade for math classes. It's not uncommon for fifth- and sixth-graders to climb the stairs to the school's second floor for math instruction at Capitol Hill Junior High, said Assistant Principal Renee Jensen.

Even so, what would happen to Mani was "really, really unusual."

Within weeks of starting first grade, Mani had moved up to fourth-grade math. In the spring, he worked on the fifth-grade math textbook in the evenings. Over the summer, he tackled the sixth-grade textbook, at the rate of two to three hours at a time, seven days a week. Vivek Chadaga helped out, but he says, "Oftentimes, Mani was the one teaching me."

That's how a nervous Mani stepped into that junior high algebra class as a second-grader.

"I felt proud, but a little embarrassed, too," he recalls. "I felt like maybe I was too far ahead in math."

The shyness Mani felt that day quickly faded. He kept up effortlessly, and teacher Alex Ford started assigning him more challenging problems. In the spring, Ford tasked a dozen or so advanced students in the class with deriving the quadratic formula, the stuff of Algebra II. Mani took the lead.

"He literally taught the rest of them the entire problem," Ford said, adding, "He could stand in front of a room full of eighth-graders and describe the solution to problems with poise and confidence and perfect mathematical reasoning."

Last year and again this fall in high-school-level Algebra II and geometry, Mani eased into the company of the older kids. Teachers and students say he has a way of showing what he knows - without showing off. His junior high classmates still talk about his quick solution to the prime factorization of 1,001 - a problem some in the class still mull over.

"He's probably smarter than all of us," added Joey Gagne, an eighth-grader in Mani's Algebra II class.

As Mani waded into the more abstract world of algebra, his dad says, he started asking insistent questions about the purpose of math. Together, they devised excuses to unleash math onto the world. On the playground swing, they spoke about formulas to calculate its acceleration. In their backyard, Mani figured out a way to use his shadow to calculate the height of an old oak tree. Then, there was the Monkey-Moon-Toffee Challenge: Mani had to calculate the shortest route to get a monkey on the moon. Toffee was the reward.

"I think we used the circumference equation," Mani said. "I wonder if I would get anything for solving this now."

Julia Chadaga says math has become a bonding experience for Mani and his dad, who readily admits Mani is out of his league these days. Mani's favorite number is 41 - a prime number, for one thing, but also his dad's age.

"I am not thinking about math every single day, every single hour, every single minute," says Mani.

He has written about 100 sonnets, on nouns, soccer ("I never would have thought about success/If I had never played my very best"), his little sister, bad haircuts and a frog named Blep. He recently researched patent law on the Internet in preparation for upcoming inventions - say, a teleportation device or an invisibility cloak. He also researched and wrote a four-page single-spaced paper on hot peppers, including a daring kitchen experiment that had him chugging glasses of milk.

"No matter what Mani does, he always takes it to the next level," said Heidi Geimer, his third-grade teacher. With weekly writing homework, he also turns in chapters of a novel, she said: "He sets his own personal standards."

Mingling with the older kids has Mani wondering about his future. He could be a striker for Barcelona's soccer team, a professional chess player, an inventor.

"There are so many possibilities," he said. "I haven't even found the mathematics I am the most interested in."

Meanwhile, his school and parents are looking ahead, too.

This year in Algebra II, he only shows up for "a little refresher here and there," said teacher Kyle Warner. Next year, he'll likely start pre-calculus. The year after, he might travel to Central High School for more math. As a sixth-grader, he could start a calculus course through the University of Minnesota's Talented Youth Mathematics Program, an honors-level college-credit alternative for middle and high school students.

Even so, said Scott Gilbert, the head of the program, "He'd still be topped out by ninth grade and have no work left to do."

Mani reminds Gilbert of fellow Capitol Hill mathematician Martin Camacho, who wrapped up the Talented Youth program several years ago at age 12 and enrolled full time at the U the following year.

Geimer hopes the school system will find ways to continue to push Mani. In any case, she doesn't doubt he will keep pushing himself. And he will stay grounded, she said: "With Mani, you know in your heart of hearts he's going to grow up and do good for the world."

Information from: St. Paul Pioneer Press, http://www.twincities.com