Wilson says he has some evidence for his claims. He gave his Calculus 3 college students a 10-question calculator-free arithmetic test (can you multiply 5.78 by 0.39 without pulling out your smartphone?) and divided the them into two groups: those who scored an eight or above on the test and those who didn’t. By the end of the course, Wilson compared the two groups with their performance on the final exam. Most students who scored in the top 25th percentile on the final also received an eight or above on the arithmetic test. Students at the bottom 25th percentile were twice as likely to score less than eight points on the arithmetic test, demonstrating much weaker computation skills when compared to other quartiles.

It’s worth noting that calculators are also more likely to be barred in math exams at research universities than at two-year colleges and regional public universities. Out of the 50 national universities ranked at the top by U.S. News and World Report, only four schools had policies allowing electronic devices on Calculus 1 exams. One explanation is that selective institutions are less likely to offer remedial math courses and generally accept students who possess a strong math background.

Why aren’t high schools taking their cue from math professors at Harvard and MIT? Because most college students won’t major in STEM subjects and won’t need advanced math knowledge for much of their work. Dan Kennedy, a high-school teacher at Baylor School, argues that to set a reasonable expectation for all students, calculators should be used because many real-world problems cannot be solved without technology. Students, he says, would be better served by learning probability, statistics, computer literacy, financial mathematics, and matrix algebra—the kind of math that requires the use of graphing calculators—not the kind of theoretical math that dominates math competitions.

David Bressoud, a math professor at Macalester College in Minnesota, has a different theory: He thinks that large research universities typically ban calculators because the devices are essentially obsolete there. “The larger universities have traditionally had computer-lab resources, [and now] it is easier to expect that all students have access to a computer,” Bressoud said. Computers, Bressoud says, are a much better tool for teaching calculus because they are more flexible and faster than calculators.

At Macalester, first-year calculus is known as “Applied Multivariable Calculus 1.” Computers are heavily encouraged in class, and professors aren’t slowly chalking away proofs and theorems on the blackboard. Unlike those at traditional college math classes, Macalester professors take the word “applied” seriously: A lecture on functions, for example, is demonstrated using the Body Mass Index, a function of height and weight used to determine whether a person is obese. Students in their first year of calculus also learn differential equations, a topic that is generally covered only when students have three semesters’ worth of calculus under their belts. The aim is that, by introducing differential equations early on, students understand how mathematical models are generated. Why? Because these models are used in many fields, including, but not limited to, economics, environmental science, psychology, and medicine.