Sets — Flashcards

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Step 1: Count the number of boys in the class. Step 2: The number is limited. Answer: It is a finite set.

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Step 1: Check for odd numbers between 7 and 9. Step 2: There is no such number. Answer: It is an empty or null set, written as {} or ∅.

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Step 1: An empty set has no elements. Step 2: The set {0} contains one element, namely 0. Answer: {0} is not empty because it has zero as its element.

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Step 1: An empty set has no elements. Step 2: The set {∅} contains one element, and that element is ∅. Answer: {∅} is not empty because it has one element.

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Step 1: Natural numbers less than 7 are 1, 2, 3, 4, 5, 6. Step 2: Write them inside curly braces. Answer: {1, 2, 3, 4, 5, 6}.

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Step 1: Notice the pattern: all are even natural numbers less than 10. Step 2: Use x : x ∈ N and x is even, x < 10. Answer: {x : x ∈ N and x is even and x < 10}.

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Step 1: Compare the elements. Step 2: Both sets have a, b, and c. Step 3: Order does not matter in a set. Answer: They are the same set because the order of elements is not important.

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Step 1: Write each element only once. Step 2: Remove repeated elements. Answer: {2, 3, 4}.