Ashlock, Robert B. <br/><br/>
Error patterns in computation :  using error patterns to improve instruction / 
Robert B. Ashlock 
 - 9th ed. 
 - Upper Saddle River, NJ :  Pearson Prentice Hall,  2006 
 - 274 p. :  ill. ;  23 cm. 
<br/><br/><label>ISBN: </label>0131198866 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Arithmetic--Study and teaching (Elementary)