In order to simplify manipulation with numbers and objects, it is possible to define both numeric and object variables by means of the num and obj keywords:

Numeric variables

num radius;
radius = numericExpression;
num radius = numericExpression;

Numeric variables

obj sphereA = objectExpression;
sphereA = objectExpression;

Both in numeric and object expressions, basic operators as +, -, * and parenthesis are allowed. Numeric constant PI is also defined. Operations between numbers and objects are not defined. It is not possible to define an object variable without initialization.