Book excerpt: With a farm of pigs as his abacus, Arthur Geisert uses elements of a search and count game to bring Roman numerals to life in this unintimidating math-concept book. First, the seven Roman numerals are equated with the correct number of piglets. Then the reader may practice counting other items—hot-air balloons, gopher holes, and more—as the remarkable adventure unfolds. (And yes, there are one thousand pigs in the etching for M!)