Calculate the corresponding "Y-axis" values of ten "X-axis" numbers. For example, if y=x^2, calculate the Y-axis values for X where X equals -5, -4, -3, -2, -1, 0, 1, 2, 3 and 4. Plot these values on the graphing paper, where the X value is the horizontal axis, and the Y value is the vertical axis.
Choose two ascending points on the graph (such as "X=2" and "X=3"). Draw a straight line from one point to the other.
Count the number of lines on the vertical axis between the two points, and write this number down as the numerator. Count the number of lines on the horizontal axis between the two points, and write this number down as the denominator. The gradient is the numerator divided by the denominator.