Below is an instruction that describes a task. Write a response that appropriately completes the request in English. Please answer in English.

### Instruction:
Addilynn went to the grocery store and bought six dozen eggs for use in her house. After two weeks, she used half of the eggs, then accidentally broke 15 of the remaining eggs while moving them to clean the shelves. How many eggs are left on the shelf?

### Response:
Since 1 dozen equals 12 eggs, then Addilynn bought 6 dozen eggs, a total of 6*12 = <<6*12=72>>72 eggs.
If she used half of the eggs, the number of eggs left is 1/2 *72 = 36 eggs.
While moving the eggs to clean the shelves, she broke 15 eggs, leaving 36-15 = <<36-15=21>>21 eggs on the shelf.
#### 21