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.
--Mathematical model building. Math modelling is the act of creating functions or equations that describe a given application or situation. In this course we mainly concentrate on business-oriented ideas such as break-even analysis or depreciation. --Matrix algebra. Matrices are collections of numbers organized in rectangular arrays.