In this sequel to One Guinea Pig is Not Enough (1998), Duke serves up a romp with subtraction instead of addition concepts. What happens when a little wooden boat is fairly bulging with pudgy guinea pigs? Twenty guinea pigs start to sink, and to save their furry skins, half must dive into the water. Thus begins the mathematical odyssey of the ten remaining guinea pigs as one by one they subtract themselves from the boat. One little pig floats away on the strings of a colorful bunch of balloons. Another bellyflops out of the picture, while still another explores himself out of the equation. At last only one guinea pig remains on the little green vessel, but “one can be fun.” Children will delight in finding all the creatures reunited on the final page, again adding up to twenty. Within each full-spread illustration frolic the lively and adorable little rodents accompanied by vibrant-hued and giant-sized numbers spelling out numerically what the text describes in mirthful language (with juicy words like “flabbergasted”). Duke doesn’t disappoint, characteristically lavishing the book with her carefree and fun-filled watercolors of irresistibly cute critters in whimsical situations that can’t but inspire chuckles while teaching a thing or two. (Picture book. 3-7)