List the rules to declare a variable in Python. Demonstrate at least 3 different types of variable uses with an example program.
Example: python variables
#Varibles Guide:
a = 5 #NUMBER
b = "Varibles!" #STRING
c = True #BOOLEN Hey, this is an edit, sorry for having it as true not True, caps matter.
d = False #BOOLEN Hey, this is an edit, sorry for having it as false not False, caps matter.