00422cam a22001454a 4500020002700000050001200027245005700039260005400096300002700150650001600177650001600193700002400209700002000233700002300253  a0309069955 (hardcover)00aQA135.500aAdding it up :bhelping children learn mathematics /  aWashington, DC :bNational Academy Press,cc2001.  axvii, 454 p. :bill. ; 0aMathematics 0aMathematics1 aKilpatrick, Jeremy.1 aSwafford, Jane.1 aFindell, Bradford.