What is the GCF of 15,18 ?
answer: 3
correct
http://www.google.com/search?q=gcf+of+15&ie=utf-8&oe=utf-8&aq=t&client=firefox-a&rlz=1R1GGLL_en___US379#sclient=psy&hl=en&client=firefox-a&hs=Bln&rlz=1R1GGLL_en___US379&q=gcf+of+15+and+18&aq=f&aqi=g4g-o1&aql=&oq=&gs_rfai=&pbx=1&fp=280187d6f0589da0