Free practice on Sets and Logic for Class 4, following the Cameroon primary school curriculum (English subsystem). Every answer is explained, so a parent who is not sure of the answer can still help.
Equal sets have exactly the same members: {1, 2, 3} = {1, 2, 3}. Equivalent sets have the same NUMBER of members but different things: {a, b, c} is equivalent to {1, 2, 3} — both have 3 members.
| Equal | Equivalent |
|---|---|
| {cat, dog} = {cat, dog} | {cat, dog} ↔ {pen, book} |
| Same members exactly | Same size, different members |
Union (∪) means COMBINING sets — put everything together, no repeats. A = {1, 2, 3}, B = {3, 4, 5}. A ∪ B = {1, 2, 3, 4, 5}. Intersection (∩) means the members that appear in BOTH sets. A ∩ B = {3}.
∈ means 'belongs to'. ∉ means 'does not belong to'. ⊂ means 'is a subset of'. ∪ = union, ∩ = intersection. Curly brackets { } enclose a set.
| Symbol | Meaning |
|---|---|
| { } | Set |
| ∈ | Belongs to |
| ∉ | Does not belong to |
| ⊂ | Is a subset of |
| ∪ | Union |
| ∩ | Intersection |
A = {1, 2, 3} and B = {3, 4, 5}. What is the intersection of A and B?
Answer: B. {3}
The intersection holds only what is in BOTH sets.
A = {1, 2} and B = {3, 4}. What is the union of A and B?
Answer: C. {1, 2, 3, 4}
The union puts all the members together.
Sets {a, b, c} and {x, y, z} have the same number of members. They are:
Answer: B. equivalent sets
Equivalent sets have the same number of members; equal sets have exactly the same members.
Which symbol means 'is an element of'?
Answer: A. ∈
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