Alferez, Merle S. <br/><br/>
Mental math / 
Merle S. Alferez. 
 - Quezon City :  MSA Publishing House,  2005. 
 - 67 p.:  26 cm. 
<br/><br/><br/>English 
<br/><br/><label>ISBN: </label>971-8740-77-5 
<br/><br/><label>LC Class. No.: </label>513.213 Al28ma