Science - physics; science - natural history; art; PE - gym and field sports; history; music. No particular order of preference, they are all important to produce well rounded and well educated children. When I taught, all children loved these subjects. A useful addition to these and the 3Rs, learned as part of the lessons, would be the effective use of a library.
Children love to learn, and, contrary to the belief of the the new age, politically correct educational theorists, they like to get it right, not look like twits when some one outside of school says what the teacher should have said, 'no, that's wrong, this is what it should be, this is how it should be done...'