They don't know where to begin, which information to use to solve them, or what to do. Some children give up before they even start. Children often enjoy stories. They're drawn into the plot and delighted by the pictures which support the plot. But, somehow, many don't find the story in mathematics story problems.
Stories have a setting, characters, problem, events related to solving the problem, and resolution.
It often helps to have children identify the parts of a problem. This often confuses children because they don't know what to do with it. They think that they have to use it. Teach children to draw a single line through information that they do not need to solve the problem so they can focus on solving the problem. Modeling this process helps children understand how they are supposed to do this.