To add fractions with different denominators, you need to find a common denominator. In this case, the common denominator is 36 because it's the smallest number that both 12 and 18 can divide evenly into. So, for 6/12, you multiply the numerator and denominator by 3 to get 18/36. And for 7/18, you multiply the numerator and denominator by 2 to get 14/36. Now you can add them together: 18/36 + 14/36 = 32/36. Finally, simplify the fraction by dividing both the numerator and denominator by their greatest common divisor, which is 4: 32/36 = 8/9.
