Some algebraic problems will ask you to find an unknown percentage increase or an unknown percentage decrease between two known factors. An unknown factor is a variable.  

When asked to find a percentage increase or decrease, use the following formula:
The % increase or decrease = the difference between the known factors divided by the base factor.  Now let’s work this out in a practice problem below.
 

Grades 6, 7 and 8 - Math - Middle School - Algebra - Percentage Operations (Advancing)

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10 Questions

1. Solve

2. By the end of the 8th grade Eva had performed in 36 dance recitals. That was equal to 82% of all the recitals that she attended. How many recitals did Eva attend by end of the 8th grade?

3. Mr. Stiller had a total of 486 history students. That was equal to 93% of the total number of geography students that he had. How many geography students did Mr. Stiller have?

4. The new soccer stadium will hold 29,900 people while the old stadium held 30,400 people. By what percentage above the new stadium did the old stadium hold?

5. 54/6 + (100/50) - (3 x 5) + (11 x 4y) =

6. Solve

7. Romy and Michelle have each been saving Barbie dolls for over 60 years. At last count, Romy had a total of 712 dolls but that only 83% of the number of dolls that Michelle had saved. How many dolls has Michelle saved?

8. 21 x 3 + (32- 11) + 6 x (15/5) =

9. What is '1,000,000,000' called?

1 zillion1 trillion

10. Solve