"If you could ask 10 friends to tea, tell me who your friends would be," begins Goldstone's (The Beastly Feast) rollicking, rhyming approach to addition and multiplication. In each of 10 spreads, the unseen narrator suggests different combinations that add up to 10, which Cahoon (Word Play ABC) interprets in vibrantly saturated spreads of an anthropomorphized menagerie. A rose-hued stage scene featuring a sextet of flamingos en pointe, partnered with four leaping frogs, for instance, illustrates the equation 6 + 4; while 8 + 2 translates into eight mouse tailors cavorting among spools and thread, joined by two plunger-toting elephant plumbers. Whenever the equations lengthen beyond two addends, the rhyming text takes on jovial patter-song silliness: "How about 1 prince, 1 painter, and 2 potters, 1 diner, 1 miner, 1 major, and 3 otters?" Finally, the book offers up the cumulative possibility of what would happen "if ALL your friends show up": it's the number 100, the magnitude of which is driven home by a page filled with thumbnail portraits of every one of the participants. Exuberantly stylish, this painless introduction to the power of 10 should prove to be many aspiring mathematicians' cup of tea. Ages 3-7. (Aug.)