How much recycled newspaper will save a tree?

Grade level: 4th – 5th grades

Skills: Fraction (multiplication/division)

Related environmental issues: Reduce/Reuse/Recycle

 

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Recycling paper prevents many trees from being cut down for paper. It is estimated that we can save one tree by recycling a stack of newspaper 3 feet high.

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  1. Sean recycled a stack of newspaper 23 feet high.  How many trees did Sean save by recycling the newspaper? Answers must be fractions in mixed numbers.
  2. To save 13 1/6  trees, a stack of how many feet of newspaper Does Sean need to recycle?  Convertfractions into mixed numbers.
  3. Maya wants to save 18 2/3trees. She gathered newspaper to recycle and made a stack of newspaper 55 feet high.  Did she gather enough newspaper? Explain.

 

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Source: Recycle Across America, Recycling facts


Answer keys

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How much energy & money do LED lamps save?

Grade level: 4th – 5th grades

Skills: Multiplication

Related environmental issues: Energy conservation

The table below shows how much electricity each light bulb uses to light your room in 1 year.

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  1. Your house has 30 light fixtures.  How much electricity do you use during a year if you use a regular light bulb for each light fixture?
  2. How much electricity do you use during a year if you use an energy saving light bulb for each house’s light fixture?
  3. How much electricity can you save if you replace all of the 30 regular light bulbs with energy saving light bulbs?
  4. The average price of 1kwh-electricity in California was 21 cents in August 2018. How much money could your family save for electricity in a year if you replaced all of the 30 light bulbs with energy saving light bulbs in a year?

 

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Answer keys

  1. 200 x 30 = 6,000 (kWh)
  2. 30 x 30 = 900 (kWh)
  3. 6,000 – 900 = 5,100 (kWh)
  4. 5,100 x 21 = 107,100 (cents) = $ 1,071