Adding and Substracting on Integers

With this applet you will be able to understand the concept of addition and substraction in integers.
You do your exploration by dragging either the blue or the red circles. Blue circles are for -1, red circles for +1. Dragging a circle into the bowl means adding while dragging a circle out of the bowl means suctracting.
For example to determine the value of 5 - 3 you put into the bowl 5 red circles and then take 3 out of the bowl. The result is 2 whichs is shown in the box above the bowl.
Try to determine the value of: -5 - (-3), -2 - 3, 5 - (-2).