The class is about heat, waves, and light. The website wants exactly the perfect answer and in the same metric system units that are stated on the calculators that are on the picture for the question, if not, it'll mark it wrong.

Set 15 Problem 5 One lens of a nearsighted person's eyeglasses has a focal length of 4&6 cm and the lens is 2 cm from the eye If the person switches tn annual lenses that are placed directly on the eye, what should be the fees] length of the corresponding annual lens