In Tang's seventh picture-book attempt to make math entertaining, sixteen rhyming riddles (answers provided) encourage readers to group numbers in order to add them more efficiently. Adults may bristle at liberties taken with syntax to clinch a rhyme ("Her recent birthday I forgot"), but readers will be absorbed by Tang's puzzles and by Briggs's velvety smooth digitally rendered art.

The seventh in a line of verse math-terpieces that began with Grapes of Math (2001), this offers 16 problem-solving shortcuts that involve grouping numbers or items. Tang not only provides answers and methods in a closing key, he is generous with hints. Opposite digitally worked, color-coded arrays of anywhere from 30 to 148 stars, sea shells, spiders, pickles, the titular potatoes, playing cards and the like, his verses open with a pair of lively introductory couplets, set the problem with a third, then suggest an approach in the fourth: "Can you add up these poor souls / For whom the bell already tolls? / In groups of ten you'll hear their cries, / Please don't turn us into fries!' " Even numerically challenged readers can count on coming away with some time and labor saving techniques for toting things up. (Picture book/nonfiction. 7-9)

Gr 3-6-Tang's seventh entry in a series that includes The Grapes of Math (2001) and Math-terpieces (2003, both Scholastic) is another winner. Each spread includes a poem consisting of neatly rhymed couplets that first set a scene ("I gaze into the evening sky,/Think great thoughts and wonder why") and concludes with a hint or suggestion as to how the objects on the opposing page might most efficiently be grouped to arrive at a sum ("When you look up to the heavens,/Try to think in groups of sevens!"). There are no overt patterns so that, as Tang says in his author's note, children are challenged "to combine numbers in smart ways, not just obvious ways." The book concludes with clear diagrams and succinct explanations providing the solutions. Briggs's computer-generated art is crisp, clear, and delightfully quirky. For example, "Sock Hop" features a loafer on guitar, work boots on drums, and a high-heeled pump on keyboard. Puzzle-loving kids will pick this up on their own, and teachers could pair it with Jon Scieszka's Math Curse (Viking, 1995) for an energizing departure from the standard math lesson.-Grace Oliff, Ann Blanche Smith School, Hillsdale, NJ Copyright 2005 Reed Business Information.