With such hopelessly inane work, many students come to feel that math is too difficult for them and that getting a good grade is all about second-guessing what the teacher's answer key says. Such worksheets are excellent for fostering rote memorization and for preventing students from learning how to think critically for themselves. Without looking, choose a soft drink. We are supposed to find the probability of choosing a cola or diet cola. Even if we make the extra assumption that each button on the machine corresponds to one type of drink, we still don't know if some drinks get more than one button.
Many pop machines stock more slots with the more popular variety.
Again, the problem is nonsensical and distant from the real world. Far and away the biggest problem with many modern textbooks is that they make complete hash out of the natural conceptual hierarchy of mathematics. If we wonder why some students have trouble thinking logically, it's partly because they are taught from disintegrated materials. They have failed miserably. Now the responsibility lies with Colorado's teachers, principals, school board members, and especially parents to be more critical of the materials used in our children's learning.