程序不会将真实答案与玩家的答案进行比较

当我运行程序时，我会输入正确的答案，但它总是将其标记为错误：

（10，'+'，2）
12
…
答错了，答案是12！

这是错误的代码部分：

Player_answer = input()
print ("...")
time.sleep (0.5)
if operation==("+"): #check answer
    answer = num1+num2  #This works out the real answer
    if Player_answer == answer:  #This works out if the player is correct
        print("That's the correct answer")
        score = score + 1
    else:
        print("Wrong answer, the answer was",answer,"!")
if operation==("*"):
    answer = num1*num2
    if Player_answer == answer:
        print("That's the correct answer")
        score = score + 1
    else:
        print("Wrong answer, the answer was",answer,"!")
elif operation==("-"):
    answer = num1-num2
    if Player_answer == answer:
        print("That's the correct answer")
        score = score + 1
    else:
        print("Wrong answer, the answer was",answer,"!")