im trying to make a simple calculator:

loop = 1
while loop == 1:
print "Welcome to Jakes' Calculator"
print "3) multiplication"
choice = raw_input("Enter a number 1-4: ")
break
if choice.strip() == "1":
a = input("enter the first number: ")
b = input("enter the second number: ")
c = a + b
print a, "plus", b, "equals", c
elif choice.strip() == "3":
a = input("enter the first number: ")
b = input("enter the second number: ")
c = a * b
print a, "times", b, "equals", c
elif choice.strip() != "1" "3" :
print "Not valid input"
loop = 1

the loop won't work, i want it to go back to the menu after it gives you an answer.

You break out of loop without calculations and you have problem with syntax. If you use input in Python2 you can just input the calculation normally 3.234 + 23.12312 as it runs the expression through eval. It is not so safe though, so use raw_input allways:

while True:
print "Welcome to Jakes' Calculator"
print "3) multiplication"
print "0) quit"
choice = raw_input("Enter the number: ").strip()
if choice == "1":
a = float(raw_input("enter the first number: "))
b = float(raw_input("enter the second number: "))
c = a + b
print a, "plus", b, "equals", c
elif choice == "3":
a = float(raw_input("enter the first number: "))
b = float(raw_input("enter the second number: "))
c = a * b
print a, "times", b, "equals", c
elif choice != "0" :
print "Not valid input"
else:
break
print
commented: this little 2 points rep for your patience and help +2

how silly of me to make a simple mistake. thanks