The Concept of a Simple Calculator

The Simple Calculator is made out of a collection of physical objects, called Tokens. In the first version of the calculator each token was either a Numeral or an Operator. Each token is the shape of the numeral/operator it represents, to enable the child to grasp its function from its form.

The tokens have the following properties:

• Each token has means to communicate with its nearest neighbours, i.e., the tokens to its left and right.
• Each token has ``a button'' which can be pressed and the ability to convey some results (e.g. via a physical display or a speaker.)