Python 3 f-string alternative in Python 2

Question

Mostly I work with Python 3. There can I write this:

print(f"The answer is {21 + 21}!")

Output:

The answer is 42!

But in Python 2, f-strings do not exist. So is the following the best way?

print("the answer is " + str(21 + 21) + "!")

Answer 1

Using format:

print("the answer is {} !".format(21 + 21))

Answer 2

There are two ways

>>> "The number is %d" % (21+21)
'The number is 42'
>>> "The number is {}".format(21+21)
'The number is 42'