SOLUTION: How many unordered sets are there of two items chosen from four?

Question 1148146: How many unordered sets are there of two items chosen from four?

Answer by ikleyn(52781) (Show Source): You can put this solution on YOUR website!
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It is the number of combinations of 4 items taken 2 at a time


     =  = 6.

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On Combinations, see introductory lessons
    - Introduction to Combinations
    - PROOF of the formula on the number of Combinations
    - Problems on Combinations
    - OVERVIEW of lessons on Permutations and Combinations
in this site.

Also, you have this free of charge online textbook in ALGEBRA-II in this site
    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this online textbook under the topic "Combinatorics: Combinations and permutations".

Save the link to this textbook together with its description

Free of charge online textbook in ALGEBRA-II
https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson

into your archive and use when it is needed.

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HOW MANY UNORDERED SETS ARE POSSIBLE THAT CONTAIN 5 OBJECTS CHOSEN FROM 12 (answered by robertb,stanbon)