Merttens, Ruth,  <br/><br/>
Adding and subtracting 

 - 31 pages :   colour illustrations ;   28 cm 
<br/><br/><label>ISBN: </label>1852700106 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Arithmetic
<br/><br/><label>Dewey Class. No.: </label>513