This is two worksheets to practice ray diagrams for lenses.
I use these in my Conceptual Physics classes and AP Physics.
This will only work for you if your students refer to the 3 principle rays as "Ray 1, 2, & 3"
Ray 1 goes in parallel to the principle axis and comes out lined up with a focal point.
Ray 2 goes through the center of the lens without bending.
Ray 3 goes in line up with a focal point and comes out parallel to the principle axis.