A simple rule of three idea is commonly used in many everyday situations. It uses a practical process to solve problems involving four values ​​of which we know three of them. Let's look at four practical steps used a simple rule of three: 1) Build a table, gathering the quantities in columns and linking each value his greatness; 2) Identify whether the magnitudes are directly or inversely, what we will see after the last step; 3) Assemble the equation as follows: if the quantities are directly