As I remember a boy from another planet was dropped on earth. Gravity didn't affect him as much. He was being chased by something and leaped over a barbed wire fence "like a deer". Also the story started out with a young earth girl at "school", she sat in her bedroom and her books and teachers were on a screen ...cutting edge stuff for a 4th grader in 1974.
You appear to be confusing two different stories that appeared in volumes of the Holt Basic Reading System. The level 13 (fourth grade) volume, Time To Wonder, included Asimov's short story "The Fun They Had." The story is about a girl in the future who goes to school at home, which is contrasted with how schooling works in our time.
The other story is the full novel The Forgotten Door by Alexander Key. It appeared in the level 15 (sixth grade) book Riders on the Earth, filling a full 100 pages of the textbook. The protagonist is from an alien world, who "falls" through the titular door and ends up on Earth. He has telepathic powers and can "lighten his feet" to leap abnormal distances when he is being chased.