This math skill teaches how to calculate the number of ways to choose a specific number of items from a larger group of identical items using combinations. It specifically explains the combination formula and how to apply it to calculate possibilities.
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Counting ways to pick N from M of a suit in a set of tiles
Test your understanding of desired outcome counting with cards by practicing it! Work through the below exercises to use it in practice.
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How many different ways can we draw 2 hearts from this set of tiles?
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The important thing to note is that only the hearts matter, we have 4 of them, and we are looking to pick 2 of the 4 in any order.
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So that's 4 choose 2. We can write it in either notation, in the first, its the 4 first and the 2 second to mean 4 choose 2. In the bracketed, or binomial notation, it's the 4 on top.
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The factorial equation for 4 choose 2 is 4 factorial, divided by, 2 factorial times 4 - 2 factorial.
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If we calculate that out, that's 6 ways to pick 2 hearts.