What are formulae?
A formula typically describes a calculation, such as addition, to be performed on one or more variables. A formula is often implicitly provided in the form of a computer instruction such as
Total fruit = number of Apples + number of Oranges.
Degrees Celsius = (5/9)*(Degrees Fahrenheit -32)
In computer spreadsheet terminology, a formula is usually a text string containing cell references, e.g.
=A1+A2
where both A1 and A2 describe "cells" (column A, row 1 or 2) within the spreadsheet. The result appears within the cell containing the formula itself (possibly A3, at end of values in column A). The = sign precedes the right hand side of the formula indicating the cell contains a formula rather than data. The left hand side of the formula is, by convention, omitted because the result is always stored in the cell itself and would be redundant.
{Source: Wikipedia}
Creating your first Formula
You can get a step by step guide to creating your first formula by following the set in the video below