Parentheses Numbers (VIDEO!)

Here is a classic puzzle: In how many ways can one arrange parentheses around a sum of N terms so that one is only ever adding two things at a time? [This is a great puzzle for students to do when they are first learning about parentheses!]

It turns out to be tricky, but in this video we come up with a good way of computing these numbers. In part II of this video, we go further and find an actual explicit formula for them!

Parentheses Numbers: Part I
Parentheses Numbers: Part II


    QUADRATICS, Permutations and Combinations, EXPLODING DOTS, and more!

    Written for educators - and their students too! - this website, slowly growing, takes all the content Tanton has developed in his books, videos, and workshops, and organizes it into short, self-contained, and complete, curriculum units proving that mathematics, at all points of the school curriculum, can be joyous, fresh, innovative, rich, deep-thinking, and devoid of any rote doing! Let's teach generations of students to be self-reliant thinkers, willing to flail and to use their common sense to "nut their way" through challenges, to assess and judge results, and to adjust actions to find success. (Great life skills!)


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