Arithmetic Teacher 38 

 - Philadelphia  NCTM  Mar. 1991 
 - 60 
 - 20091215 
 - Arithmetic Teacher  38 .
<br/><br/><label>ISSN: </label>1679-656X 
<br/><br/><label>Dewey Class. No.: </label>AMT 2009  / 2009