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How to keep a perfect 20/20 vision for 2020? First, find out what is your risk of vision impairment is. Use this calculator, and you'll also learn how to prevent it.

The Black Hole Collision Calculator lets you see the effects of a black hole collision, as well as revealing some of the mysteries of black holes, come on in and enjoy!

The books vs. e-books calculator answers the question: how ecological is your e-book reader? 📚

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