Use the sliders to change the numerators and denominators for the given fractions. The black rectangle in the middle represents 1 whole. The red and green are portions according to the ratios you chose with the sliders. Drag the colored pieces into the middle using the diamond at the bottom of the rectangle. TO ZOOM: Hold Shift and scroll up or down with Mouse/Trackpad TO DRAG: Hold SHIFT, Click and Drag Mouse/Trackpad