8.1.6 Calculator Exploration: Percentage Conversions
The calculator can be accessed on the left-hand side bar under Toolkit.
In this exploration, you will use the calculator for percentage conversions.
To Write a Percentage as a Fraction or a Decimal
Remember that the percent sign means “out of one hundred.” So, 5% means , and this is how it is entered on the calculator.
Enter 5% as on the calculator, and click the equals sign, or hit Enter on your keyboard.
The key sequence is
The calculator gives the fraction in its reduced form with the decimal equivalent.
Activity: Converting Percentages to Fractions
Try writing these percentages as fractions and as decimals.
Clear the last calculation before you start, and remember that % means “out of one hundred.”
(a) Entering 88% as 88 divided by 100 gives 0.88, so .
To Write a Decimal Number as a Percentage
To write a decimal number as a percentage, multiply the number by 100%. The calculation is quite easy to do without the calculator because you can move the decimal point two places to the right. For example, 0.8 becomes . Let’s check that the calculator does the same. Enter the calculation . The calculator gives the answer 80.
Remember that you must include the % sign when you quote the answer.
Activity: Converting Decimals to Percentages
Use the calculator to write these decimal numbers as percentages:
(a) To convert 0.28 to a percentage, multiply by 100%. Using the calculator, multiply by 100, and then attach the % sign when you write the answer down, as follows: .
Note: We do not use the percent key when converting a decimal to a percentage. When you use the percent key, it is converting the value to its decimal equivalent. Here, you are just trying to find the value that belongs in front of the percent sign.
(b) . (Did you remember to attach the % sign when you wrote the answer down?)