Did you know? Mass of a regulation tennis ball (57 g) is 10 x Mass of a USA quarter (25c piece) (5.67 g)
Pop. of Hong Kong, China (7.3 million people)
/fact/population-of-hong-kong-china
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If this was a standard unit ...
Yes, there's now a book based on these numbers. Oxford University Press: July 2018.
Click here to learn more about it.
Click here for Podcast: Andrew Elliott interviewed for New Books Network.