Helen the hippo and her friends are preparing for thanksgiving at Helen's house. Helen baked 12 chocolate chip cookies yesterday and 18 raisin cookies and 12 chocolate chip cookies this morning. How many chocolate chip cookies did Helen bake?
Helen baked 12 chocolate chip cookies yesterday. 
This morning, she baked 18 raisin cookies and 12 chocolate chip cookies. 

That means that in total, Helen baked 30 cookies this morning. 

Therefore, the answer is that Helen baked 24 chocolate chip cookies in total.