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.
Sets, relations & functions worksheet with answers
1.Easy
A = {6, 8, 10}B = {3, 10, 12, 20}|U| = 8
|A − B| =
2.Easy
Let A = {b, c, d, x} and B = {1, 2}. Find |𝒫(𝒫(A))|.
A = {b, c, d, x}B = {1, 2}
|𝒫(𝒫(A))| =
3.Medium
Exactly one region of the Venn diagram is the set (A′ ∩ C) ∩ (B ∩ C). Click its number.
(A′ ∩ C) ∩ (B ∩ C)
- 1region 1
- 2region 2
- 3region 3
- 4region 4
- 5region 5
- 6region 6
- 7region 7
- 8region 8
4.Medium
A survey of 71 people finds that 36 own a laptop (L), 36 a tablet (T) and 22 a smartwatch (W). 14 own L and T, 12 own L and W, 11 own T and W, and 3 own all three. How many are in L only?
|U| = 71
|L − (T ∪ W)| =
5.Hard
The arrow diagram shows a function f: A → B with A = {1, 2, 3, 4} and B = {a, b, c, d}. Click the description that fits f.
f = {(1, c), (2, d), (3, b), (4, a)}
- 1injective, not surjective
- 2surjective, not injective
- 3bijective
- 4neither
6.Hard
The functions f and g on {1, 2, 3, 4, 5} are given by their tables. Find (f ∘ f)(5).
f: 1 ↦ 3, 2 ↦ 5, 3 ↦ 5, 4 ↦ 1, 5 ↦ 3g: 1 ↦ 2, 2 ↦ 2, 3 ↦ 2, 4 ↦ 1, 5 ↦ 5
(f ∘ f)(5) =
Answer key
- 1. |A − B| = 2
- 2. |𝒫(𝒫(A))| = 65536
- 3. region 1
- 4. |L − (T ∪ W)| = 13
- 5. bijective
- 6. (f ∘ f)(5) = 5
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