"High School Mathematics Foundation Strengthening Textbook": This textbook is specially written for students with weak mathematics foundation. It usually includes a lot of examples and exercises, and each concept has detailed explanations and steps. It covers all the topics of high school mathematics, including algebra, geometry, trigonometry, function and so on.

Khan Academy: Khan Academy is an online learning platform that provides free mathematics education resources. It includes hundreds of math video tutorials, covering topics from basic knowledge to advanced concepts. Students can choose appropriate courses according to their own level and needs.

Tutorial books and workbooks: Some tutorial books, such as compulsory mathematics I and compulsory mathematics II, provide high school students with clear mathematical theoretical knowledge and a large number of exercises. These books are usually divided into chapters according to difficulty, which is suitable for students to study in stages.

Math learning applications: Some math learning applications, such as Photomath and Mathway, can help students solve math problems and provide step explanations. These applications usually cover various mathematical topics and can be used anytime and anywhere.

Math forums and online communities: Some math forums and online communities, such as Stack Exchange and the math section of Reddit, allow students to ask for help when they encounter difficulties and exchange learning experiences with other students.

Math tutor or class: If students' math foundation is weak, consider taking a math tutor or looking for a math tutor. Individualized teaching can better meet the needs of students and solve specific mathematical problems.