Piano practice is the bane of a boy's existence. He'd rather be playing the infield, but his mother is absolute about piano lessons: ""We don't have quitters in this family."" Only his tango-dancing Nana Hannah, with whom he spends a week while her sprained ankle heals, seems to know how to nudge him toward the ivories: She takes an interest in baseball, and he is inspired by her love of music. When they sit together and bang out a four-handed duet of ""Take Me Out to the Ball Game,"" the boy's diamond buddies, peeking through the window, go wild. Sharing, caring, and a patch of common ground--Bottner (Hurricane Music, 1995, etc.) knows the ingredients, and fashions them into a minor ode to encouragement. Bluthenthal's brashly cartoonish illustrations are technically sophisticated, particularly nice in the swooping lines of Nana in tango mode.