Real is the head used for real (floating-point) numbers.
_Real can be used to stand for a real number in a pattern.
You can enter a floating-point number of any length.
You can enter a number in scientific notation by using the form mantissa
*^
exponent.
You can enter a floating-point number in base b using b
^^
digits. The base must be less than 36. The letters a-z or A-Z are used in sequence to stand for digits 10 through 35.
