Let A = {b, c, d, x} and B = {1, 2, 3}. Find |A × B|.
Sets, relations & functions worksheet with answers
1.Easy
A = {b, c, d, x}B = {1, 2, 3}
|A × B| =
2.Easy
The Venn diagram shows every element of the universal set U and of the sets A and B. Find |A ∩ B′|, the number of elements of A ∩ B′.
A = {4, 7, 10, 11, 12, 20}B = {3, 4, 6, 7, 12, 16, 20}|U| = 11
|A ∩ B′| =
3.Medium
A survey of 50 people finds that 21 own a laptop (L), 25 a tablet (T) and 26 a smartwatch (W). 7 own L and T, 14 own L and W, 14 own T and W, and 5 own all three. How many are in exactly two of the three sets? Call the number n.
|U| = 50
n =
4.Medium
Each number in the Venn diagram is the number of elements in that region. Find |(A′ ∩ C) ∪ (A ∩ B)|.
|U| = 46
|(A′ ∩ C) ∪ (A ∩ B)| =
5.Hard
How many different relations are there on a set with 2 elements? Call the number N.
|X| = 2
N =
6.Hard
The arrow diagram shows a function f: A → B with A = {1, 2, 3, 4} and B = {a, b, c, d, e}. Click the description that fits f.
f = {(1, c), (2, e), (3, d), (4, a)}
- 1injective, not surjective
- 2surjective, not injective
- 3bijective
- 4neither
Answer key
- 1. |A × B| = 12
- 2. |A ∩ B′| = 2
- 3. n = 20
- 4. |(A′ ∩ C) ∪ (A ∩ B)| = 23
- 5. N = 16
- 6. injective, not surjective
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