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.
Arithmetic (from the Greek á¼ÏÎ¹Î¸Î¼ÏÏ arithmos, number) is a branch of mathematics that consists of the study of numbers, especially the properties of the traditional operations between themâaddition, subtraction, multiplication and division.