Whether studying or teaching mathematics at any level, one is likely to encounter difficulties simply because mathematics is different. For most subjects, careful reading with comprehension is a good start, but while reading mathematics is valuable, it requires a different way of thinking to be comprehended. Thus, it is often frustrating for a child, or even an adult going to college, and for those assisting with the learning such as parents and teachers.
The frustration comes from putting out effort with poor results. One might approach history by reading, then after learning facts think how or why something happened. In fact, most subjects are not too different from this, read and enjoy the reading, then dissect what is there. With mathematics one can read and not succeed. The underlying key is in understanding the material, so mathematics must be explained. Books too often have many words placed there for accuracy, but only apply to a special case. This is when a teacher can say what is really the kernel of what is being done.
Thinking logically is key. Mathematics is a cause and effect subject. If I do something, what will happen, and what does it mean? Then string steps together making a transitive string, until you get to the final answer. And thoughts must be reinforced with practice.