00285nam a2200109Ia 4500082001900000100002200019245007300041260003100114300002000145500000500165700000500170  a510.9bF889.WS  aFreudenthal, Hans  aWeeding and sowing; preface to a science of mathematical educationb  aDordrechtbD. Reidelc1978  aix, 314p. Index  a  a