The amount of time will, of course, vary from student to student and family to family, but, on average elementary level, homeschool students spend only about 2 to 3 hours a day studying (excluding reading literature) and still surpass students in schools. But if you wish your students to excel in life, we believe it takes more time than that to do well. But no precise number is valid for all. Nevertheless, double that time or even more would not be unreasonable in some cases. It obviously depends on a number of factors: available time; educational goals; grade level, number of courses, temperament, other obligations, etc.
The Jesuits discovered long ago that students do not like doing the same learning activity more than two times in a row. So they broke it up with contests, field trips, other subjects (such a perhaps geography or history), different approaches, etc. Some homeschooling parents make Wednesdays a different sort of day, leaving Mondays and Tuesdays, and then Thursdays and Fridays, for the routine classes, but thus only two times in a row. But family life often solves this problem in unexpected ways!