Duncan, John <br/><br/>
New mental arithmetic 
John Duncan 
 - London:  Collins,  1970, 
 -  127p. 
<br/><br/><br/>eng 
<br/><br/><label>ISBN: </label>0003187306 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Arithmetic
<br/><br/><label>Dewey Class. No.: </label>513  / DUN