6.3.2 Multiplying Mixed Numbers and Fractions on the Calculator
The calculator can be accessed on the left-hand side bar under the Toolkit.
In this exploration, you will learn how to multiply fractions on the calculator.
When you used the calculator to add fractions, you didn’t have to think too hard about entering them correctly, because the calculator follows the correct order of operations. It prioritizes division over addition, and the fractions are automatically entered as you intend.
More care is needed for multiplication of fractions, because division and multiplication have equal priority where order of operations is applied.
To be sure that the calculator is performing the calculation that you want it to, it is best to insert parentheses around each fraction.
So, to multiply , you must enter the calculation as on your calculator.
The proper key sequence is:
The calculator should show:
Note how the calculator automatically converts into before it displays the answer as a fraction and a decimal.
Activity: Multiplying Fractions
Try the next examples for yourself.
(a) Remember to put parentheses around the fractions.
Using the calculator:
To do the calculation without the calculator, you need to change the mixed number into an improper fraction. You can enter the fraction as a mixed number on the calculator.
Using the calculator, you can enter the mixed number as a sum. You need parentheses around the whole of to show that you are multiplying all of this by .
(Here, the top window of the calculator only displays the first eight of the 14 decimal places. The entire rounded output is shown in the window below.)
- The calculator follows orders of operations. It calculates results in parentheses first, then exponents, then multiplication and division, and lastly addition and subtraction.
- When multiplying fractions on the calculator, enclose each fraction or mixed number in its own set of parentheses.