They don't have laptops or iPads.
It is work time, but slanted more towards fun. Not coloring, not crafts, but yes, things like math rods or math games. I got the impression that there are various worksheets and workbooks as well as other educational items in the boxes. DD9 also has math boxes in her classroom and it works a lot like that. I don't think this is reading time--I believe that is a different part of the day.
It may be that she will also use this to replace other activities for him. NOt sure. She basically said I should send in whatever I thought would be helpful and that she was going to try to find ways to differentiate however she could, so heaven knows I want to jump on that. DS nearly lost his mind in academic pre-K last year, so we know he is not likely to cruise through K contentedly unless something is done to help him out.
He does like Sudoku. I thought about physical games, like some ThinkFun stuff, but I wasn't sure. He loves Rush Hour, but that would be tempting to play with and might get wrecked.