What trash was thrown away the most?

Grade level: 4th – 6th grades

Skills:DECIMALS  (Comparison)

Related environmental issues: Recycle


Almost every activities we do in our lives leaves behind some type of trash. The United States threw away 4.51 pounds of trash per person every day in 2017. The table below shows how much each trash was thrown away per person a day in 2017.


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Write <, >, or = in each square to compare a true statement about the two decimal numbers.

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Source: U.S.Environmental Protection Agency, 2019. Advancing sustainable materials management: 2017 fact sheet. 


Answer keys

1. >
2. <
3. <
4. >


Factful Environmental Math Problems (2020)

Just published and now available from Amazon  (paperback)

About this book

The objective of Factful Environmental Math Problems is to cultivate our young people’s skills to analyze and evaluate fact-based data for understanding our world, while improving their math skills and critical thinking skills.

With the rise of the Internet and new technology, building skills to analyze and evaluate fact-based data becomes increasingly important for our young people to prepare for this rapidly changing world. These skills minimize their chances of being brainwashed by false information and making uninformed decisions and ultimately help develop their critical thinking skills. (Read more)

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Published: March 26, 2020

Price: $6.25

What U.S. company uses that largest amount of solar power?

Grade level: 4th-5th grades

Skills: Comparing numbers / Subtraction (Decimal numbers)

Related environmental issues: Renewable Energy 

Many large companies in the United States have installed solar panels to use renewable energy to meet their energy demand and to become more environmentally sustainable.

The table below shows top 5 companies that use the largest amount of solar power in the United States.

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1. Arrange companies from greatest to least.

2. How much more or less solar power does Target use than Walmart?

3. How much more or less solar power does Amazon use than Apple?

Source) SEIA (Solar Energy Industries Association), 2019. 2018 Solar Means Business Report


Answer keys

1. Apple, Amazon, Target, Walmart, Switch

2. 242.4 – 208.9 = 33.5        33,500 (kilowatts) more solar power

3. 393.3 – 329.8 = 63.5        63,500 (kilowatts) less solar power