Pyhton Invalid Syntax IF statement

I'm trying to make a quiz in python but I keep getting invalid syntax errors.

#This is for addition questions.

if (question=add)  <---- That is where i get the error
for i in range(0,10):
    first_number_add=random.randint(1,50)
    second_number_add=random.randint(1,50)
    answer=int(input(str(first_number_add) + '+' + str(second_number_add) + '='))
    sum=first_number_add+second_number_add
    if (answer==sum):
        print ('Correct')
        stats['correct'] += 1
    else:
        print ('Incorrect.')
        stats['incorrect'] += 1