So in order to add the fractions together you need to first find a common denominator. For the very first problem you can use 63 as a denominator because 7*9=63. Now for the numerator. So you have 4/7 and 8/9. We just multiplied 7 by 9 so now we need to do that for 4 also. 4*9=36. Now we have 36/63. For 8/9 we multiply 8 by 7 to get 56. Now we have 36/63 + 56/63. Once you add those together you simplify your answer.