Factful math: Grade 3rd-5th
Math skills: Average
Related issues: Water / SDGs6: Clean Water and Sanitation
Not all the people in the world has access to toilets, and about 500 million people still practice open defecation. The number of people practicing open defecation decreased by 245 million between 2015 and 2020. On average, about how many people gained access to toilets per year between 2015 and 2020?
A. 50
B. 100
C. 200
ANSWER A
245 million / 5 = 49 million = about 50 million
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Factful math: Grade 4th-6th
Math skills: Multiplication
Related Environmental issues: renewable energy
The world’s largest offshore wind farm Hornsea 2 in the UK has 165 wind turbines.
A single rotation of a wind turbine takes 6 seconds and generates energy to power a home for a day. How many homes can the Hornsea 2 wind farm power in an hour of operation?
ANSWER 3
1 hours = 3600 seconds
A wind turbine rotates [3600/6=600] times in an hour.
A wind turbine generates energy to power 600 homes in an hour.
There are 165 wind turbines in the Hornsea 2 wind farm, so the wind farm can generate energy to power [600 x 165 = 99,000] homes in an hour.
Source: BBC. Hornsea 2: North Sea wind farm claims title of world’s largest [https://www.bbc.com/news/science-environment-62731923].
