Operations on Sets
Venn diagram
A drawing using overlapping regions to show the relationships between sets.
| English | Venn diagram |
|---|---|
| Bahasa Melayu | Gambar rajah Venn |
| 中文 | 文氏图 |
How it is used
A survey of 40 students shows 25 like tea, 18 like coffee and 10 like both. Placing 10 in the overlap gives 15 for tea only and 8 for coffee only, so 40 − (15 + 10 + 8) = 7 like neither.
Where it shows up in SPM
In the Operations on Sets chapter (Form 4) and revisited in Probability. Paper 1 shades regions like A ∩ B′; Paper 2 gives a labelled Venn diagram with an unknown x and asks you to form and solve an equation.
Don't confuse it with
Open the chapter: Operations on Sets →
Frequently asked questions
How do I fill in a Venn diagram when there is an overlap?
Always start from the centre. Write n(A ∩ B) in the overlap first, then subtract it from n(A) and from n(B) to get the 'only' regions.
This stops you from counting the shared members twice.
The Venn diagram has an unknown x, what do I do?
Add up every region in terms of x and set the total equal to n(ξ). For example, if the regions are 12, x, 7 and x + 3, and n(ξ) = 30, then 12 + x + 7 + (x + 3) = 30, giving 2x + 22 = 30, so x = 4.