BusinessWeek’s Stephen Wildstrom reviews Casio’s ClassPad math calculator which you may want to consider for your high school or college student. The exec summary: $150 graphical calculator with a touch-sensitive screen that lets you get a hands-on feel for geometry and algebra. The downside: Texas Instruments dominates this segment and there are entire curriculums built around it. Bottom line, says Stephen, “It’s the best sort of educational technology: a tool that can deepen understanding.”