However, what would you do if you were given an expression such as Clearly you would hope to rely on a calculator to perform the tedious arithmetic. Before working on this expression, lets work on a simpler one. Take and find the rational number that represents it. Your calculator probably has the additional key . This is a very useful key.
Many calculators have parentheses keys.
In the first case you get 95, in the second 47. The general rule of arithmetic is that when there are no parentheses, multiplication and division is performed before addition and subtraction. Press for the clear button, or turn the calculator off and on again. Note Not all calculators are alike. We have given methods that are widely accepted by the most popular calculators.