Fundamental ideas are the basic concepts or principles that serve as the foundation for understanding a subject. They help to simplify complex topics by breaking them down into essential elements. For example, in mathematics, fundamental ideas include numbers, operations, and equations, which are crucial for solving problems. In science, fundamental ideas encompass theories and laws that explain natural phenomena, such as the laws of motion or the theory of evolution. These core concepts guide research and experimentation, allowing scientists to build upon existing knowledge and make new discoveries.