Looks hard, but here are two methods.
10:17
Geometric Pigeonhole Principle question
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Além de ½ a b sin(C)
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The Genius Way Computers Multiply Big Numbers
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This has a neat, clever solution.
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As 10 melhores PROVAS em matemática do ensino médio | jensenmath.ca
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Can you crack this beautiful equation? – University exam question
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Can you solve this Cambridge Entrance Exam Question?
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