Fractions and Your Calculator
When calculator use is not allowed, be sure to write out all the steps on your paper to avoid
careless errors. When calculator use is allowed, you can use your calculator to solve fraction
problems. When you do, ALWAYS put each of your fractions in a set of parentheses. This will
ensure that your calculator knows that they are fractions. Otherwise, the order of operations will get
confused. On a scientific calculator, you can write the fraction in two different ways:- You will have a fraction key, which looks similar to “a .” If you wanted to write , you’d
type “5 a 6.”- You can also use the division key, because a fraction bar is the same as “divided by.” Be
aware that your answer will be a decimal for this second way, so we recommend the first.On a graphing calculator, you’ll use the division bar to create fractions. Keep in mind that, whatever
calculator you are using, you can always turn your fractions into decimals before you perform
calculations with them. Just be aware that the answer won’t always be exact.Adding and Subtracting Fractions with the Same Bottom
To add two or more fractions that all have the same bottom, simply add the tops and put the sum over the
common bottom. Consider the following example:
Subtraction works exactly the same way:
Adding and Subtracting Fractions with Different Bottoms
In school you were taught to add and subtract fractions with different bottoms, or denominators, by finding
a common bottom. To do this, you have to multiply each fraction by a number that makes all the bottoms
the same. Most students find this process annoying.
Fortunately, we have an approach to adding and subtracting fractions with different bottoms that
simplifies the entire process. Use the example below as a model. Just multiply in the direction of each
arrow, and then either add or subtract across the top. Lastly, multiply across the bottom.