First, you want to turn each mixed number into an improper fraction. So you get -10/3 + 12/5. Then you want to get the same denominator, and the LCD happens to be 15. You get -50/15 + 36/15. Addition is commutative, so you can do something like this: 36/15 - 50/15. You can do 36-50=-14, and then add the denominator to get -14/15.
