Set Union and Intersection

How do you denote the empty set?

• {}

• ∅

• []

• ()

If Set A = {x | x is a natural number less than 5} and Set B = {x | x is a natural number less than 3}, what is A ∩ B?

• {1, 2}

• {1, 2, 3}

• {2, 3, 4}

• {1, 3}

What is the union of the sets {1, 2} and {2, 3, 4}?

• {1, 2, 3}

• {1, 2, 3, 4}

• {2, 3}

• {1, 2, 4}

What is the result of A ∪ ∅ for any set A?

• A ∪ ∅ = A, since the union of any set with the empty set is the set itself.

• A ∪ ∅ = ∅, since the union with the empty set results in the empty set.

• A ∪ ∅ = A ∪ A, since the union of a set with itself is the set itself.

• A ∪ ∅ = A ∩ A, since the union and intersection of a set with itself are the same.

If Set A = {1, 2} and Set B = {2, 3}, what is A ∪ B?

• {1, 2}

• {1, 2, 3}

• {2, 3}

• {1, 3}

What is the union of the sets {a, b} and {c, d, e}?

• {a, b, c, d, e}

• {a, b, c}

• {b, c, d, e}

• {a, d, e}

What is the difference between a subset and a proper subset?

• A subset contains all elements of another set, while a proper subset has at least one element less than the other set.

• A subset can be equal to another set, while a proper subset cannot be equal to another set.

• A subset is always larger than the set it is compared to, while a proper subset is always smaller.

• A subset must have at least one element, while a proper subset can be empty.

If Set A = {x | x is an even number} and Set B = {x | x is a prime number}, what is A ∩ B?

• A ∩ B = {2}

• A ∩ B = {4}

• A ∩ B = {6}

• A ∩ B = {}

What is a set?

• A set is a collection of distinct objects, considered as an object in its own right.

• A set is a single object with no elements.

• A set is a type of function in mathematics.

• A set is a collection of similar objects only.

What does it mean for Set A to be a subset of Set B?

• Set A contains elements that are not in Set B.

• Set A is a subset of Set B if every element of A is also an element of B.

• Set A and Set B are identical sets.

• Set A is larger than Set B.