The View from Saturday is a novel by E.L. Konigsburg that explores the conflicts, tribulations, and relationships of a sixth-grade teacher, Mrs. Olinski, and the four children—Noah, Nadia, Ethan, and Julian—that she chooses to represent her class during the upcoming Academic Bowl contest. In addition to Mrs. Olinski, each of the four children (who call themselves "The Souls") have stories, and each child narrates a chapter that centers on his or her story.
Noah is the first student to be selected for the team because he's a capable leader and is always first to have the answer. However, he has to learn to set aside his selfishness and constant desire to be the hero to trust in his teammates and share the spotlight.
Ethan is constantly being compared to his older brother, Luke, who's proficient at both sports and school. Ethan's struggle is to overcome the perceived deficiencies that fester in the comparison—that he can't measure up—and learn to accept himself for all the great things he is.
Nadia moves to New York with her recently divorced mother while her father stays in Florida. She needs to adjust to this new life and accept grown-up problems like divorce if she is to become a grown-up herself.
Julian is the new kid in school and suffers through being bullied, particularly because of his Indian heritage. He faces the constant inner struggle of maintaining the moral high ground despite his desire to fight back.
Mrs. Olinski, who became a paraplegic after a car crash, must overcome her own internal suffering, resulting from how others (including her own students) view her along with a latent anger about her lot in life.
The short answer is that there's not just one problem in the story, but several smaller, individual problems. Thematically, however, you could say that the overarching problem that binds everyone's story into a coherent whole is learning to be a better person, overcoming issues inside yourself and how that ultimately breeds success. Each character learns from the best parts of the others how to fight their own internal fights.