I haven't taught any of the classes yet. I just got my access to the curriculum materials and was getting ready to make my samples for the first class. Class syllabus for the single crochet class specifies an H hook. The Skinny Scarf specifies an H hook. If I click on the picture of the Smart Phone Cover, the web page specifies an H hook for this too, but the PDF file with the pattern in it, which I would expect to use as the handout in class, specifies a G hook. The gauge for the Scarf is 13 sc and 14 rows = 4 inches, but the gauge for the Smartphone Cover is 16 sc and 18 rows = 4 inches, consistent with a smaller hook for the Smartphone Cover. I expect that gauge is not really critical on these projects, after all these are beginning students and they probably won't get the gauge just right anyway, especially since they will probably only have the one hook that was specified, but how do you explain the fact that the pattern calls for a different hook than they were told to purchase when they signed up?