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What Hierarchy?

Discrete Mathematics Level 1

How many trapezoids are there in the figure above?

Bonus: Generalize this.

9 10 11 12

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Excel in math and science

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It's hard to learn from lectures and videos

Learn more effectively through short, interactive explorations.

Used and loved by over 6 million people

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including olympiad champions, researchers, and professionals.

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That seems reasonable. Find out if you're right!

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by Pi Han Goh

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