With positive slope the line moves upward when going from left to right ... This is a typical downward sloping demand curve which says that demand declines as price rises. This is a special case of a ...
The slope of a line can be 'seen' to be sloping uphill ... gradient\,of\,line\,EF = - \frac{2}{5}\) Horizontal lines have a gradient that is zero, ie they are not sloping uphill or downhill.
The National 4 section shows how to calculate the gradient of a slope using the vertical height and horizontal distance. A similar approach can be used for calculating the gradient of a line ...