Are you smarter than a 5th grader? Chapel Hill 10-year-old scores 5 on AP calculus exam

On any regular day, eleven-year-old Paul Rosu seems just like every other kid at Smith Middle School — but he recently achieved something few his age have. He received a 5 on his AP Calculus AB exam, the highest possible score, and may have been the only fifth-grader to take the exam last year.

Paul Rosu, now a sixth-grader, took the AP Calculus AB exam at the end of his fifth grade year, when he was only 10 years old.

His father Radu Rosu, a statistician, estimated the number of other kids Paul’s age that might have also taken the exam last year. Using the data made available from College Board, he determined that of the 144 people nationwide who were younger than 9th grade, the likelihood of a 5th grader taking the exam was zero with a margin of error greater than or equal to one. 

Therefore, Radu Rosu said, Paul very well could’ve been the only kid his age who took the test.

Paul said he didn’t start out that advanced, but began doing an online math program called IXL in the second grade and got interested in the subject.

His math career has only advanced since then. Paul said he liked how advanced AP Calculus was. His least favorite topic was trigonometric substitution, while he found limits the easiest.

Paul was a fifth-grader at Rashkis Elementary School in Chapel Hill last year when he prepared for the AP exam. He said that besides his dad, his fifth grade teacher was very important in pushing him to succeed.

“She was occupied teaching the other kids,” he said. “But I think she was my first teacher that understood that it would be more beneficial to work on other stuff.”

His teacher, Rachel Devon, said Paul seemed like a normal, cool kid that worked well with his classmates.

“He explained things really well, and he liked to teach but never overstepped with other classmates,” Devon said.

She said she communicated with the Rosu family to decide what was best for Paul. They decided that before each unit, Paul would take a pretest, and if he placed out of that he could keep working on his calculus or studying for the SAT.

However, Devon said they agreed she wouldn’t be the one who’d be teaching Paul the more advanced math, since it had been a long time since she’d taught that level of math. 

“One of the areas I helped him with was the test taking strategies and working through those problems,” she said.

When the test results came out and showed that Paul had received a 5, Devon and the Rosu family were happy but not surprised.

“Beforehand I was pretty scared,” Paul said. “But when I got into it, it seemed easier than what I’d done in practice.”

Paul’s father said he’s worried about the credit Paul will receive for the exam.

“The UNC system has rules for giving credit for the AP,” Radu Rosu said. “One of the very strange things is you get credit at the university, but you do not get credit in high school, which is kind of absurd.”

But overall, Paul’s family and teachers know that he has a bright future ahead of him.

“I know we will see his name in the future doing great things,” Devon said.

Paul said that someday he wants to be a computer engineer, and despite being a Chapel Hill local, he wants to attend NC State or MIT — but that’s a long time away for the eleven-year old.

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