In mathematics when two variables are next to each other the implied operation is multiplication. This makes many equations and formulas more simple. For example, shown below is the general form of the quadratic equation

In this case the coefficient being next to the variable means to multiply the two together.

Shown below are a couple two more examples of 1) a number and variable and 2) constant and a variable.

Multiplication is a common operation in math and there are many ways of expressing the operation. Shown below are some other ways of expressing multiplication.

A dot between two numbers denotes multiplication in mathematics. The formal name for the dot symbol is an interpunct.

Two expressions placed next to each other and separated by parenthesis are assumed to be multiplied together.

When entering an expression in a computer multiplication is represented using the asterisk symbol.