Alferez, Merle S. <br/><br/>
Mental math tricks :   addition techniques / 
Merle S. Alferez. 
 - Quezon City :  MSA Publishing House,  2006. 
 - 139 p.:   ill.  23 cm. 
<br/><br/><br/>English 
<br/><br/><label>ISBN: </label>971-8740-89-9 
<br/><br/><label>LC Class. No.: </label>513.213 Al28ma