How are we protected from dangerous air pollutions?


Grade level: 3rd-5th grades

Skills: Place value and expanded notation

Related environmental issues: Air

Area level: National

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

Source: American Lung Association 


Answer keys

  1. 0
  2. ten thousands
  3. b
  4. 2,000
  5. 30,000