000 00269nam a2200109 a 4500
001 4140
005 20140414131943.0
008 090218s19uu xx 00 eng d
050 _aTR 372.7
_bW55 2006
245 _aWhat are numbers? (6to 99). Act. bk. 6.
541 _eM3993
999 _c112630
_d112630