Helen the hippo and her friends are preparing for thanksgiving at Helen's house. Helen baked 27 cookies yesterday 13 cookies this morning and 23 cookies the day before yesterday. How many cookies did Helen bake till last night?
Yesterday, Helen baked 27 cookies. 
This morning, she baked 13 cookies. 
That means she's baked a total of 40 cookies so far. 
The day before yesterday, she baked 23 cookies. 
That means she's baked a total of 63 cookies in the last three days.