500
What's with this way of using a microscope, "Amelia could not find the specimen on the slide even though she always started with the stage at its lowest setting and brought it up using the slide adjustment knobs."
What is two things wrong - you should always start high and move and slide away from or down when looking through the eyepiece AND the coarse and fine adjustment knobs are used to move the slide up and down; the slide adjustment knobs are used to move the slide left, right, away and toward the viewer.