Combining means

Students will learn how to solve four different types of problems involving means. In the first type of problem, the mean of the original group is given, and the mean of the group plus one member is given. The objective here is to find the value of the added member. Basically, the mean of group A is x, and the mean of group A plus member m is y, what is the value of m? In the second type of problem, the mean and size for each of two groups is given, and the objective is to determine the mean overall. In the third type of problem, the overall mean is given, the size of each of two groups is given, and the mean of one of the two groups is given. The objective is to find the mean of the other group. In the fourth type of problem, the size of a group and its mean are given. We are told the value of member m, and from this, must determine the mean of the group after m is removed.