Formulas

As seen in the beginners guide you can enter in operators such as + – / and *. Formulas must start with a = and can use brackets.

The Use of Brackets

Brackets are used in excel to determine which operator to use first.

For example:
=(A1+A2)*A1

In the above example the brackets sum A1 with A2 before multiplying by A1.

Note that a formula does not need to contain a cell reference. It could purely have a formula containing numbers.
For example:
=10*12-2

It even be a combination of cell references and numbers. See diagram

The formula in one cell can also be based on a formula in another cell.