00538nam a2200181 a 4500 20140412111344.0 041005s19uu xx 00 eng d 0-04-446709-0 TR(GS 513.2'12 M95 1997 Murphy, Stuart Elevator magic / Stuart Murphy. New york : Harper collins, 1997. 32 Mathstart Explains the concept of subtraction through a rhyming text about a descending elevator Subtaction 105197 105197 0 0 0 EL EL TR 2004-10-05 Lib. Fund 0 TR(GS 513.2'12 M95 1997 E9556 2014-04-12 00:00:00 2014-04-12 BK