PSAT stands for Preliminary SAT. It is good practice for the SAT, which contains the same types of questions. The PSAT tests critical reading, math problem solving, and writing skills.
The PSAT Critical Reading sections include reading comprehension questions about full-length and paragraph-length passages. They also include sentence completions.
The PSAT Writing sections include multiple-choice questions on grammar, usage, word choice, and organization. There is no essay section (unlike on the SAT), but schools are provided with a practice essay to help students prepare for the SAT essay.
The PSAT Math sections include multiple-choice questions and grid-in questions, which require the student to generate a response. Topics include numbers and operations; algebra and functions; geometry and measurement; and statistics, probability, and data analysis. Math topics that most first-semester juniors have not yet covered are excluded from the test.