Arithmetic Teacher 28 

 - Philadelphia  NCTM  Jan. 1981 
 - 60 
 - 20091215 
 - Arithmetic Teacher  28 .
<br/><br/><label>ISSN: </label>1679-656X 
<br/><br/><label>Dewey Class. No.: </label>AMT 2009  / 2009