###Human: Brenda bakes 20 cakes a day. She does this for 9 days and then sells half of the cakes. How many cakes are left with Brenda?, ### Assistant: After 9 days, Brenda bakes 20 * 9 = 180 cakes.
After she sells half of them, the remaining will be 180 / 2 = 90 cakes. 
 So the answer is :  90