FInd the LCD (Least Common Denominator) of all of the numbers, or a number that all of them are a multiple of. In this case, it would be 270. Then multiply the numerators by the number the denominators were multiplied by to get 270.
1/2: 2*135=270, and multiplying 135 by the numerator, 1, is 135, so it would be changed to 135/270
8/9: 9*30=270, and multiplying 30 by the numerator, 8, is 240, so it would be changed to 240/270
10/15: 15*18=270, and multiplying 18 by the numerator, 10, is 180, so it would be changed to 180/270
Adding 135/270, 240/270, and 180/270 is 555/270, which would reduce to 2 1/18.
That means that the answer is 2 1/18.