Crafty ninjas take on both math and samurai masters to win a tasty taco treasure.Ten young ninjas and their plucky Siamese cat are hot on the trail of some tasty grub before they lose it to a rival gang of kid samurais and their petulant pup. Chaos ensues until the ninjas' smooth moves turn the coveted tacos into taco salad for everyone to savor, a meal that unmasks a racially diverse group of boys and girls. Underlying the rollicking adventure is a math component about fact families, with ninjas dividing into different equations that equal 10: On a lone fold-out page, "Five ninjas chop! Five do spin kicks!" It's refreshing to see a fairly conceptually sophisticated math board book, though the ninjas occasionally clump so tightly that distinguishing how many are in each group is challenging. Illustrations are pure fun, an homage to old-school comics and arcade games, with spiky speech bubbles, motion lines, classic video-game display type, and flying projectiles that suggest that ninjas will "crash" or "swoop" in at any second. The contrast of the black-suited ninjas against the bright, complementary color scheme enhances their dynamism. With its relentless rhythm and enough punctuation that grown-ups can really ham it up, it's a blast to read aloud.Wannabe ninjas will flip over this board book's cool vibe, awesomely frenetic art, and dual math and sharing narrative. (Board book. 2-4)