We cannot take half of 9 people. The even numbers, then, are the numbers divisible by 2: 2, 4, 6, 8, and so on. The odd numbers are 1, 3, 5, 7, and so on. If you do not know half of some even number, you can find it by decomposing it mentally into two even numbers whose half you do know.
To draw a shape, line or angle accurately using a compass and straightedge (ruler). Sometimes you are also allowed to use a protractor and triangle.
1. geometric mean-the mean of n numbers expressed as the n-th root of their product. statistics-a branch of applied mathematics concerned with the collection and interpretation of quantitative data and the use of probability theory to estimate population parameters.