Is the mean of the squares of two numbers greater than, or less
than, the square of their means?
Can you use the diagram to prove the AM-GM inequality?
There are thirteen axes of rotational symmetry of a unit cube. Describe them all. What is the average length of the parts of the axes of symmetry which lie inside the cube?
There are four unknown numbers.
The mean of the first two numbers is 4, and the mean of the
first three numbers is 9.
The mean of all four numbers is 15.
If one of the four numbers is 2, what are the others?