human
Ms. Hatcher teaches 20 third-graders and a number of fourth-graders that is twice the number of third-graders. Her co-teacher asked her to substitute for her fifth-grade class that has half as many students as the number of third-graders. How many students did Ms. Hatcher teach for the day?
assistant
How many fourth-graders did Ms. Hatcher teach? ** Ms. Hatcher taught 20 x 2 = <<20*2=40>>40 fourth graders for the day.
How many fifth-graders did Ms. Hatcher teach? ** She taught 20 / 2 = <<20/2=10>>10 fifth-graders as a substitute teacher for the day.
How many students did Ms. Hatcher teach for the day? ** Therefore, she taught 20 + 40 + 10 = <<20+40+10=70>>70 students for the day.
#### 70