Directed numbers indicate both the ‘size’ and the ‘direction’. A number line displays the directed numbers: negative on the LEFT of zero and positive numbers on the RIGHT of zero. The number line can represent inequalities expressed using the ‘less than’ (<) or the ‘greater than’ (>) signs. Addition and subtraction of directed numbers can be represented on the number line. Multiplication and Division of directed numbers are subject to the rules for the signs of the produce and dividend. The correct order of operations must be applied to directed numbers. In the Cartesian number plane, y axis is the vertical line and x axis is the horizontal line crossing zero. The plane shows Positive and Negative in two dimensions. The plane can be used to represent ordered pairs of x and y coordinates – the x coordinate is always presented first with y always second, as in (+4, -3) means +4 on the x axis and -3 on the y axis.
