The number and length of school holidays differs significantly across OECD countries, meaning the number of instructional days in primary and secondary education ranges from 162 days a year in France to more than 200 days in Israel and Japan. The higher the level of education, the greater the number of instructional hours per school day. Students in OECD countries are expected to receive on average 4.3 hours of instruction per day in primary school, rising to 5.2 hours in upper secondary school. On average across OECD countries, around half of primary schools’ compulsory curricular time is focused on reading, writing and literature; mathematics; and science, amounting to 2.2 hours per school day. In lower secondary education this falls to only 1.8 hours per day. There are wide variations across OECD countries in the organisation of the learning time within and outside the classroom but there has been a recent trend of increasing classroom instruction time dedicated to core subjects such as mathematics, and a reduction in the time spent doing homework outside the classroom.