###Human: There are 21 cherry tomatoes on the tomato plant.  2 birds eat one-third of the tomatoes.  How many are still left on the tomato plant?, ### Assistant: The birds eat this many tomatoes: 21 / 3 = 7 tomatoes.
There are this many tomatoes left on the plant: 21 - 7 = 14 tomatoes. 
 So the answer is :  14