I'm working informally with my 6-year-old swho acquired the math bug earlier this year and is now doing late 2nd-3rd grade level material. Mostly we just chat about stuff, and he teaches and drills himself. I'd like to start him on some printed worksheets, though, to see how comfortable he would be working in a second-third grade class setting.

The two sources of worksheets I've browsed so far are the Singapore Math books, and materials printed off the Enchanted Learning site. I wondered if other parents have found sources of especially good elementary school curricular or enrichment materials in math.

Many thanks in advance for your thinking!