Most of us are familiar with percentages but explaining how to work with percentages to our kids is a different story. Homework Unlocked is here to help. Homework Unlocked offers homework help to parents so you can help your kids excel in math. Here, Homework Unlocked reviews the basics of percentages.
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Working with Percentages
Percentage is another way of saying per 100. You can always find a percentage by dividing a part by a whole and then multiplying by 100.
Example 1. If you completed 7 out of 9 questions correctly on an exam, what percentage did you get correct?
Step 1. Convert the fraction, in this case into a decimal 7 divided by 9 = 0.78
Step 2. Multiply your decimal by 100 and add a percentage symbol. 0.78 x 100 = 78%
Example 2. After eating a lovely dinner at a restaurant, you left 18% gratuity. If you left $9, how much was your total bill?
Step 1. Underline the relevant information
After eating a lovely dinner at a restaurant, you left 18% gratuity. If you left $9, how much was your total bill?
Step 2. Convert the words into mathematical expressions.
18% of the bill equals $9
18%X = $9, X = the price of the bill
We are working with a percentage, so let’s first convert our percentage to a decimal.
Y% really means Y divided by 100,
Therefore 18% = = 0.18
Now let’s put this into our original equation
0.18X = 9
Step 3. Now that we have rewritten our equation- Let’s solve it! We need to isolate X. We can do this by dividing each side by 0.18.
the 0.18 cancelled on the left leaving us with
The meal cost 50 dollars.
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