00285nam a2200121Ia 450000500170000000800410001704100080005808200150006610000230008124500310010426000200013530000080015520260720174706.0260720s2003    xx            000 0 und d  aeng  a510.2 NIEH  aNiederman, Derrick  aHard-to-solve math puzzles  aNew Delhic2003  a92p