If Set A = {1, 2, 3} and Set B = {1), which of the following is true?

The correct answer is Option 1) A - B = {2, 3}.

Key Points

• Set A = {1, 2, 3}
• Set B = {1}
• A - B means elements in A that are not in B.
• So: A - B = {2, 3}

Additional Information

• Option 2 – Incorrect: A ∩ B = {1}, not {1, 2, 3}.
• Option 3 – Incorrect: A × B = {(1,1), (2,1), (3,1)} — Cartesian product, not a set of numbers.
• Option 4 – Incorrect: A Δ B (symmetric difference) = (A ∪ B) - (A ∩ B) = {2, 3}.
• Summary:
  • Set difference (A - B): Elements in A but not in B
  • Intersection (A ∩ B): Elements common to both
  • Union (A ∪ B): All elements from both sets
  • Symmetric difference (A Δ B): Elements in A or B but not both
  • Cartesian product (A × B): All ordered pairs (a, b) such that a ∈ A, b ∈ B