the first thing is , you have to have the same denominater , which in this case is 60 ,but what ever you do to the bottom number you also have to do to the top number , so 11/12 is now 55/60 and 2/5 is now 24/60 , 55/60 + 24/60 = 79/60 = 1 19/60 , ,I hope this helps