One way to attend math lectures is to have already read the chapter in the textbook and attempted to understand it. That way, the lecture addresses the gaps in

One way to attend math lectures is to have already read the chapter in the textbook and attempted to understand it. That way, the lecture addresses the gaps in your knowledge and you can ask questions. This time-intensive strategy might be suboptimal in the long run if it reduces the time available for doing homework / sample problems, which is almost certainly the most effective way to actually learn the material.