00330nam a2200121 a 450000500170000000800410001702000140005805000240007224500180009626000520011430000080016665000340017420140414132121.0120822s19uu    xx            00    eng d  a188828739  aTR 372.7bC167 2000  aCalvert math.  aHunt Valley, Maryland :bCalvert School,c2000.  a262  aMathematics-study & teaching.