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Math Grade 6-8 Answer Key

Math: Percent of a Number

Finding a part of a whole using percents

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Math: Percent of a Number

Finding a part of a whole using percents

Math - Grade 6-8

Instructions: Read each problem carefully. Show your work and write each answer as a complete statement.
  1. 1

    Find 25% of 80.

    Twenty-five percent is the same as one-fourth.

    Twenty-five percent of 80 is 20 because 0.25 x 80 = 20.
  2. 2

    Find 10% of 450.

    Ten percent of 450 is 45 because 0.10 x 450 = 45.
  3. 3

    Find 60% of 35.

    Change the percent to a decimal before multiplying.

    Sixty percent of 35 is 21 because 0.60 x 35 = 21.
  4. 4

    Find 15% of 200.

    Fifteen percent of 200 is 30 because 0.15 x 200 = 30.
  5. 5

    Find 5% of 320.

    You can find 10% first and then take half of that amount.

    Five percent of 320 is 16 because 0.05 x 320 = 16.
  6. 6

    A shirt costs $40. What is 30% of the price?

    Thirty percent of $40 is $12 because 0.30 x 40 = 12.
  7. 7

    A class of 24 students has 75% of the students present. How many students are present?

    Seventy-five percent is the same as three-fourths.

    Eighteen students are present because 0.75 x 24 = 18.
  8. 8

    Find 125% of 48.

    One hundred twenty-five percent of 48 is 60 because 1.25 x 48 = 60.
  9. 9

    A restaurant bill is $60. You want to leave a 20% tip. How much is the tip?

    Twenty percent means 20 out of 100, or 0.20.

    The tip is $12 because 0.20 x 60 = 12.
  10. 10

    Find 35% of 90.

    Thirty-five percent of 90 is 31.5 because 0.35 x 90 = 31.5.
  11. 11

    A video game costs $50. It is on sale for 40% off. How much is the discount?

    This problem asks for the amount taken off, not the final sale price.

    The discount is $20 because 0.40 x 50 = 20.
  12. 12

    Find 12% of 150.

    Twelve percent of 150 is 18 because 0.12 x 150 = 18.
  13. 13

    A water bottle holds 64 ounces. You drink 50% of it. How many ounces do you drink?

    Fifty percent means one-half.

    You drink 32 ounces because 0.50 x 64 = 32.
  14. 14

    A store has 80 backpacks. If 15% are red, how many red backpacks are there?

    There are 12 red backpacks because 0.15 x 80 = 12.
  15. 15

    Find 8% of 250.

    You can find 10% of 250 and adjust from there, or multiply by 0.08.

    Eight percent of 250 is 20 because 0.08 x 250 = 20.
LivePhysics.com Math - Grade 6-8 - Answer Key