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?
After 9 days, Brenda bakes 20 * 9 = <<20*9=180>>180 cakes.
After she sells half of them, the remaining will be 180 / 2 = <<180/2=90>>90 cakes.
#### 90