My apologies - it was lesson 27 that was throwing me! Many thanks to Julie from Activities from Learning for breaking it down for me. I thought I might have missed some important step, but really the point of the lesson is to stretch the kids from doing straightfoward percentages and fractions into thinking through larger dollar amounts (which can still be seen in groups of 100). Kind of like the suggestion about visualizing it as a multiple-abacus problem, as suggested as well.

Thanks, all you supportive math people!

Kelly Cole