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

Arbor Day

green-leaves-clip-art-1267255Grade level: 4 – 5th

Skills:  Place value (large number)

Related environmental issues:  Environmental Events

Area level: National

Arbor Day  is an annual observance that encourages individuals and groups to plant trees and care for them. Arbor Day was first observed in in Nebraska in 1872.  More than one million trees were planted on the first Arbor Day.

  1. Write one million in numbers.
  2. How many thousands make one million?

Source:  Arbor Day Foundation

Answer keys

  1. 1,000,000
  2. one thousand thousands