How does your plastic use affect marine life?

Grade level: 5 – 6th grades

Skills: Multiplication and Division

Related environmental issues: Plastic Waste 

A whale was found dead on the Murcian coast in southern Spain in late February after swallowing 64 pounds of plastic waste.

Dead Whale Project of Greenpeace Philippines


Most plastic grocery bags are thrown away after being used, and millions of tons of plastic bags end up in the ocean. Those plastic bags have killed marine birds and turtles that confused plastic bags for jellyfish and plankton. The amount of plastic waste found in the ocean in a year is equivalent to five plastic grocery bags for every foot of coastline in the world.

  1. How many grocery bags are found in 1 mile of coastline in a year? (1mile = 5,280 feet)
  2. How many grocery bags are found in 1 mile of coastline in a month?
  3. Every month, 25 volunteers gather at their 1-mile beach to pick up plastic waste.  How many grocery bags does each volunteer need to pick up to clean their beach?
  4. 4.It is reported that the amount of plastic waste will double by 2025. How many grocery bags will be found in 1 mile of coastline in a year of 2025?


Source) New York Times, February 12, 2015. Study Finds Rising Levels of Plastics in Oceans


Answer keys

  1. 26,400 bags (5,280 x 5 = 26,400)
  2. 2,200 bags (26,400 ÷ 12 = 2,200
  3. 88 bags (2,200 ÷ 25 = 88)
  4. 52,800 bags (26,400 x 2 = 52,000)


IS it better to have higher fuel efficiency target or lower?

Grade level: 5 – 6th grades

Skills: multiplication

Related environmental issues: Climate Change

While former President Obama set high fuel efficiency* target to reduce  greenhouse gas emissions from our vehicles, the Trump administration has been trying to loosen the target so that car makers don’t need to worry too much about the amount of greenhouse gas their vehicles emit. The Obama target was to make vehicles that run 54.5 miles per gallon on average by 2025.


2018 Prius C can run 45.5 miles per gallon on average

  1. The Obama administration required vehicles that were made in 2016 to run 35.5 miles per gallon on average. Suppose you bought a black vehicle in 2016 that runs 35.5 miles per gallon and you will buy a red vehicle in 2025 that runs 54.5 miles per gallon in the future. Which car runs farther on one gallon of gasoline?
  2. Both of your vehicles have a tank that can hold 15 gallons of gasoline. How many more or less miles does the red vehicle run than the black vehicle on 15 gallons of gasoline?


Note) Fuel efficiency is a measure of how many miles a vehicle can travel on a gallon of gasoline. Fuel efficient vehicles need less gasoline to go a given distance.


Answer keys

1. red vehicle in 2025

2. 285 miles more   (54.5 – 35.5 = 19   19 x 15 = 285)