Looped Calc

x=int(raw_input("How many equations would you like to enter?"))

def Add(a, b):
    return a + b

def Sub(a, b):
    return a - b

def Multi(a, b):
    return a * b

def Divi(a, b):
    return a / b

def Power(a, b):
    return a ** b

def Mod(a, b):
    return a % b

while x>0:
    a = float(raw_input("a: "))
    op = raw_input("operation: ")
    b = float(raw_input("b: "))

    if op == "+":
        answer = Add(a, b)
        x=x-1
    elif op == "-":
        answer = Sub(a, b)
        x=x-1
    elif op == "*":
        answer = Multi(a, b)
        x=x-1
    elif op == "/":
        answer = Divi(a, b)
        x=x-1
    elif op == "^" or op == "**":
        answer = Powder(a, b)
        x=x-1
    elif op == "%" or op == "mod":
        answer = Mod(a, b)
        x=x-1
    else:
        answer = "Error: Invalid Operand"

    print answer