How are we protected from dangerous air pollution?

Grade level: 4th – 6th grades

Skills: Place value (whole numbers)

Related environmental issues: Air

Clean air is essential for our health.The United States has protected Americans from dangerous air pollution that cause asthma, lung diseases, and early death by enacting the law called the Clean Air Act. It is estimated that the Clean Air Act will save at least 230,000lives by 2020 in this country.


  1. What digit is in the tens place of 230,000?
  2. What place is the 3 in 230,000?
  3. How many thousands are in this number?
  4. How many hundreds are represented by the 2?
  5. How many ones are represented by the 3?
  6. Which number represents 230,000?
a.23  x 102
b.23 x 103
c.23 x 104
d.23 x 105


Source: U.S. EPA, Clean Air Act Overview.

Photo: WWF


Answer keys

2.Ten thousands




The 225 Math Quizzes That Will Make You An Environmental Expert (2019) is available from  (paperback)

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How many more wild giant pandas do we have now?

Grade level: 6th – 8th grades

Skills: Percentage

Related environmental issues: Biodiversity & Deforestation

[The use of a calculator is permitted]

Giant panda has long been on the endangered species list because the forests they live in China have been destroyed as the population in the country grows. However, due to conservation efforts made by the Chinese government, wild panda numbers have been increasing. The pandas are still at risk but they are now off the endangered species list.

According a survey, there are 1,864 giant pandas in the wild, and the population has grown by 16.8% over the last decade.  The survey also found that 66.8% of wild giant pandas live within protected panda nature reserves in China, while the rest live outside of the protected areas.


  1. How many wild giant pandas were there 10 years ago? How many more giant pandas do we have now? Round to the nearest ones.
  2. How many giant pandas live outside of the protected panda nature reserves? Round to the nearest ones.


Source: WWF, 2015. Panda population grows nearly 17 percent

Photo: WWF


Answer keys

  1. There were 1,596  pandas ten years ago. The population increased by 268 [116.8/1864 = 100/X]
  2. 619       [1,864 x (1 – 0.668)]