Sets

2

Contents:

A Set notation [9.1, 9.2]

B Special number sets [9.2]

C Interval notation [9.2]

D Venn diagrams [9.3]

E Union and intersection [9.4]

F Problem solving [9.3, 9.4]

Opening problem

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A survey of 50 tea-drinkers found that 32 people surveyed put

milk in their tea, 19 put sugar in their tea, and 10 put both

milk and sugar in their tea.

How many of the people surveyed have their tea with:

² milk but not sugar ² milk or sugar

² neither milk nor sugar?

A set is a collection of objects or things.

A set is usually denoted by a capital letter.

For example: E is the set of all year 11 students who study English.

C is the set of all cars parked in the school’s car park

P is the set of all prime numbers less than 10.

These sets could be written in the form: E=fyear 11 students who study Englishg

C=fcars parked in the school’s car parkg

P=f 2 , 3 , 5 , 7 g

where the curly brackets are read as ‘the set of’.

A SET NOTATION [9.1, 9.2]

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Y:\HAESE\IGCSE01\IG01_02\057IGCSE01_02.CDR Wednesday, 17 September 2008 11:08:04 AM PETER