00291nam a2200121Ia 450000500170000000800410001704100080005808200130006610000180007924500420009726000210013930000090016020260720174718.0260720s1963    xx            000 0 und d  aeng  a513 MORM  aMorton Robert  aModern arithmetic through discovery-5  aNew Jerseyc1963  a344p