4 (number)

Mathematics 
In mathematics, the number four is an even number and the smallest composite number. Four is also the second square number after one.
A small minority of people have four fingers on each hand and four toes on each foot. Four squared is 16, and four doubled is 8.

In geometry, quadrilaterals or tetragons are a kind of shapes called polygons have four sides and vertices, to which squares are quadrilaterals with sides of same length and vertices of the same wideness.

Category:Square numbers
Category:Integers