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7th Grade Math / Lesson 6: Word Problems: Percents

Word Problems
What will we be learning in this unit?


  • In this lesson you will learn how to solve problems involving percents.

    Vocabulary words are found in this purple color throughout the lesson. Remember to put these in your notebook.


Percents


    Percentages are ratios that compare numbers to 100. The word percent means parts per hundred.

  • Suppose you got a 7 out of 9 on a quiz and you wanted to know what percent that was. You would set it up as a proportion like this:

    7 = ?       This is comparing 7 out of 9 to "how many"
    9  100     out of 100 (percent).

  • Or in other words, if 9 was equivalent to 100, 7 would be equivalent to what?

    These proportions are set up using the following model:

       Portion that you have/want          =     %
    Total that you should have/want           100


Percents


    Percentages are ratios that compare numbers to 100. The word percent means parts per hundred.

  • Suppose you got a 7 out of 9 on a quiz and you wanted to know what percent that was. You would set it up as a proportion like this:

    7 = ?       This is comparing 7 out of 9 to "how many"
    9  100     out of 100 (percent).

  • Or in other words, if 9 was equivalent to 100, 7 would be equivalent to what?

    These proportions are set up using the following model:

       Portion that you have/want          =     %
    Total that you should have/want           100


Percents


  • Use the model to set up the problems.
     Portion     =       %
      Total                100
 
1)  There were 34 students out of 146 that attended the dance. What percent of the students attended?
 
 
 
2)  55% of the people were from the south. There were 60 people altogether. How many were from the south?
 


Percents


Use the model to set up the problems.

Portion = %
Total      100

Examples
1) There were 34 students out of 146 that attended the dance. What percent of the students attended?

34   = %       portion = 34,   total = 146
146  100

2) 55% of the people were from the south. There were 60 people altogether. How many were from the south?

Portion =    55       portion is unknown, total = 60
   60           100


Percents

To solve these proportions:

If we go back to our quiz example. You got 7 out of 9. What percent is that?

7 = ?        Find two numbers on a diagonal that you have.
9  100     The 7 and the 100.


Percents


Percents