Answer:
The individual members of a set are called its elements.
For example for the set A = {days of the week}, the elements
of A are Sunday, Monday, Tuesday, Wednesday, Thursday, Friday,
Saturday
For the set B = {prime numbers less than 16}, the elements
of B are 2,3,5,7,11,13
The symbol ∈ is used to indicate that an object is an
element of a set, so Monday ∈ A means Monday is an element
of A.
The letter n before a set denotes the number of elements in
the set, so n(A) = 7 and n (B) = 6.
