Japanese 15-year-olds came out ahead of their international counterparts in terms of applied mathematics, but had the worst record when it came to reading books and finding time to study on their own, a survey showed Tuesday.

The survey, by the Organization for Economic Cooperation and Development, covered roughly 265,000 15-year-olds from 28 OECD members as well as four nonmember countries.

Some 5,300 students from 133 Japanese high schools nationwide took part in the Program for International Student Assessment. The probe involved exams as well as oral interviews.