game.py

import random


def main():
    while True:
        a, b = random.randint(1, 10), random.randint(1, 10)
        expr = "{} + {}".format(a, b)
        print "What is {}?".format(expr)
        try:
            given_answer = int(raw_input('> '))
        except ValueError:
            print 'Wrong. Not a number.'
        else:
            right_answer = eval(expr)
            if given_answer == right_answer:
                print 'Correct!'
                break
            else:
                print 'Wrong. The right answer was {}.'.format(right_answer)
    print 'Game over.'

main()