It's BASIC, my dear Legs. Or so the newest and brightest of the kid sleuths, seventh-grade computer whiz Chip Mitchell, makes it seem. With best-friend Legs Feinberg as his Watson and tough, sneaky Kate Marconi a more-than-worthy rival, Chip solves a big-time computer-brains theft, an employee murder that company executives had blamed on a ""killer robot,"" and a clumsy bank programmer's swindle for which the bank officials were about to nab computer-mischief-maker Kate. Living in a rundown duplex with his sculptor aunt and a weird collection of pets, but supported in high electronic style by a traveling oil-company-consultant Dad, motherless Chip starts small by proving to his math teacher that using computers isn't cheating. . . and ends, in his tenth case, by besting a college student in a contest. With clever Kate as temporary ally, Chip locates a hypothetical Soviet sub on his home computer before his rival on the University's million-calculations-a-second ""Honeyrock 7000"" can do so. Chip's mind zips through these puzzles with finesse, while his active seventh-grade body zips from roller rink to corporate headquarters, from Crazy Marvin's Electronic World to the Underground video games arcade. The upcoming chip-savvy generation will gobble up his cases BYTE by BYTE.