A sentence which is either true or false is called a statement.
Examples:
(1) " January has 31 days” is a statement.
(2) "Null set is a subset of every set” is a statement.
(3) "All girls are studious” is not a statement.
(4) "Apoorva is honest” is not a statement.
Some sentences depend on a variable for its truth value (i.e., true or false).
e.g., “2+4+6+…2n=2n” is true for n=1 but false for n=2, n=3 etc.
As the above sentence is definitely true or definitely false for a particular positive integral value of n, the sentence is a statement and it depends on 
for its truth-value. Such statements are called predicates and are symbolised as P(n).
