Adding and multiplying percents

Adding and multiplying percents

Knowing how to add and multiply percentages is very useful in our daily life. Do you know how much sales tax you are going to pay for your new purchases? What is the sale price after discount? How do banks calculate interest? We will learn more in this section.


  • 1.
    One video game is $25 before 12% sales tax. How much is 4 video games after tax?

  • 2.
    When Kim was in grade 5, she was 130 cm tall. In grade 6, she was 20% taller than last year. In grade 7, her height has increased by 15%.
    How tall was Kim when she was in grade 7?

    Did Kim's height increase by 35% from grade 5 to grade 7? Explain.

  • 3.
    A bank pays a compound interest of 5% to any account with $10000 annually. How much will be there in an account with $10000 after 3 years?