[justify][b]Double integrals show their operation through the GeoGebra applet below. The integration results change when you directly modify both the function and the integration limits by entering values into the specified input fields.[/b][/justify]

Use a double integral to find the volume of the solid that is bounded above by the plane[br][math]z=4-x-y[/math] and below by the rectangle [math]R=\left\{\left(x,y\right):0\le x\le1,0\le y\le2\right\}[/math].