How many species are threatened with extinction?

Grade level: 5th grades

Skills: Place Value 

Related environmental issues: Biodiversity

At the present time, there are 28,338 kinds of plants and animals (species) that are at risk of becoming scarce within the foreseeable future in the world. They are threatened with extinction mainly because they lost their homes. Humans are responsible for the habitat loss when they destroy their habitats by developing housing, highways, industry, and agriculture.


1. what is the value of the underlined digit in 28,338?

2. What digit is in the tens place in 28,338?

3. What place is the 2 in 28,338?

4. What is the relationship between the values of the underlined digits?

  • 28,338 and 28,338
  • 28,338 and 28,338

Sources: IUCN Red List of Threatened Species (Table 1-b), 2019


Answer keys

1. 8,000

2. 3

3. ten thousands

4. When comparing the underlined digits, the first 8 represents 8 thousands, whereas the latter 8 represents 8 ones

When comparing the underlined digits, the first 3 represents 3 hundreds, whereas the latter 3 represents 3 tens

young protesters demand an end of the age of fossil fuels — Has the fossil fuels production decreased in the United States?

Grade level: 4th – 6th grades

Skills: Line graphs 

Related environmental issues: Energy & Climate Change


To ask for immediate action on climate change, millions of young people and adults around the world skipped school and work and participated in protests on September 20, 2019. They demanded an end to the age of fossil fuels.


[Photo] Young protesters in New York City

The line graph below shows the amount of fossil fuels produced in the United States between 2000 and 2018.


Screen Shot 2019-09-20 at 3.26.32 PM


  1. In what year did the United States produce the largest amount of fossil fuels?
  2. In what year did the United States produce the least amount of fossil fuels?
  3. Between what two consecutive years, did the fossil fuel production drop significantly?
  4. Between what wo consecutive years, did the fossil fuel production increase significantly?
  5. Has the fossil fuel production in the United States decreased or increased over the years?


PDF version



Sources: U.S. Energy Information Administration, 2019. Energy Overview, Table 1.1 Primary Energy overview.



Answer keys

1. 2018

2. 2005

3. between 2015 and 2016

4. between 2013 and 2014 and between 2017 and 2018

5. Increased