canvas.coordsfor circles using coordinate system in tkinter code example

Example 1: tkinter text in canvas

self.canvas = Canvas(root, width=800, height=650, bg = '#afeeee')
self.canvas.create_text(100,10,fill="darkblue",font="Times 20 italic bold",
                        text="Click the bubbles that are multiples of two.")

Example 2: canvas.create_oval parameters

id = C.create_oval ( x0, y0, x1, y1, option, ... )