In this activity students find gradients and use the numbers to fill in a paint by numbers style activity. Ideal for KS3 students. Have students break this down between them (there are far too many gradients to calculate by one person), maybe in groups of 2 or 3. Loads of finding gradients from two points, extension at the end to find the equations of the lines. Once they have their gradients they use the code to associate colours to the picture. It should create an image of Batman. There is an extension included.