Mathematics for IGCSE & O level - Sets (Section 2 - No. 30)
What set is represented by the notation {x | x is a day of the week}?
The set of all numbers.
The set containing all the letters in the word 'week'.
The set of all days of the week.
The set of even numbers.
Explication
The notation defines a set based on its elements, here days of the week.