Tug of War
Like the Incey Wincey Spider game, this game is designed to get children used to moving along a number line either side of a central point, which makes it a great precursor to negative numbers. The second version of the game is at a higher level as decisions have to made rather than relying solely on chance. In this case, children are practising addition and subtraction, and looking at all
possibilities, so that they can move the number of spaces that suits them best. Tug Harder take this game a little further by explicitly introducing a number line which includes negative numbers.
Pics at http://www.heligirl.com/wp-content/uploads/2010/06/Tug-O-War.gif