Sumdog does one thing well: it tricks kids into doing math and literacy drills by wrapping them in mini-games and classroom competitions. Parent and teacher reviews are consistently positive about skill improvement, and the adaptive learning engine is solid.

It's not groundbreaking or wildly imaginative—it's the digital equivalent of making vegetables taste good by adding cheese. But sometimes that's exactly what you need. If your kid groans at worksheets but will happily race their friends through multiplication problems on a screen, Sumdog delivers.

Best used as a supplement to real instruction, not a replacement. And keep an eye on kids who get stressed by competition—the racing element motivates some kids and deflates others.