Very Simple Python Calculator

def Addition():
x = int(raw_input("first number: "))
y = int(raw_input("second number: "))
print 'Your result is: ' + str(x+y)
raw_input("press enter to exit")

def subtraction():
x = int(raw_input("first number: "))
y = int(raw_input("second number: "))
print 'Your result is: ' + str(x-y)
raw_input("press enter to exit")

def multiply():
x = int(raw_input("first number: "))
y = int(raw_input("second number: "))
print 'Your result is: ' + str(x*y)
raw_input("press enter to exit")

def divide():
x = int(raw_input("first number: "))
y = int(raw_input("second number: "))
print 'Your result is: ' + str(x/y)
raw_input("press enter to exit")

choice = int(raw_input("Press 1 for addition, 2 for subtraction, 3 for multiplication, or 4 for division: "))
if choice == 1:
Addition()
elif choice == 2:
subtraction()
elif choice == 3:
multiply()
elif choice == 4:
divide()
else:
print 'Invalid Selection'