"Merttens,Ruth" <br/><br/>
Abacus evolve Textbook 1 (5) 

 - uk  ,Pearson Education  2007 
 - 80 
<br/><br/><label>ISBN: </label>9780602575816 
<br/><br/><label>Dewey Class. No.: </label>510  / T-1216