multiplication (original) (raw)

The usual operator is the cross with its four arms of equal length pointing northeast, northwest, southeast and southwest: ×. Other options are the central dot ⋅ and the tacit multiplication operator. In many computer programming languages the asterisk is often used as it is almost always available on the keyboard (Shift-8 in most American layouts, as well as dedicated key if the keyboard has a numeric keypad), and this is the operator likely to be used in a computer implementation of a reverse Polish notation calculator. In Mathematica, the space can sometimes function as a multiplication operator, but more experienced users warn novices not to rely on this feature.

Just as with addition, multiplication is commutative: x⁢y⁢z=x⁢z⁢y=y⁢x⁢z, etc.

The iterative operator is the Greek capital letter pi:

which is a compact way of writing a1×a2×…×an.