# 8.1.7 To Write a Fraction as a Percentage

You can use the same method, multiplying by 100%, to write a fraction as a percentage. For example, enter into the calculator, then multiply by 100. It’s useful, though not essential, to put parentheses around the fraction. The calculator shows , or 12.5. Therefore, . ## Activity: Making Percentages From Fractions

Use the calculator to write these fractions as percentages, giving an exact answer followed by a decimal, rounded to 2 decimal places, where necessary.

(a) ### Comment

Enter the fraction, then multiply by 100. Remember to attach the percent sign when you give your answer. (a) , or 83.33%. Note: Remember, do not use the percent key when converting a fraction to a percentage.

(b) (b) , or 0.25%. (c) (c) , or 157.14% ## The Percent Key on the Calculator

You may have noticed that there is a percent key on the calculator in the top row of keys below the number pad. There are some calculations where using this key will save you time, but be careful, as the calculator does not always behave how you may expect it to.

Enter on the calculator. The calculator converts 5% to a fraction, but does not give the decimal equivalent. So the calculator can help you convert a percentage to a fraction, but it does not change the fraction to a decimal. Also, the calculator does not help when you convert a decimal or a fraction into a percentage. For these reasons, it is better to avoid using the % key on the calculator for conversions, and to divide or multiply by 100 instead.

### To recap:

• To write a percentage as a fraction or a decimal, write the percentage as a number divided by 100 and click on the equals sign, or hit Enter on the keyboard.
• To write a decimal number or a fraction as a percentage, multiply by 100 on the calculator and then attach the % sign when you give your answer.
• Entering a percentage followed by the percent key and clicking equals gives the percentage as a fraction only.

8.1.6 Calculator Exploration: Percentage Conversions

8.1.8 Find a Percentage of a Number