Install foamCalcEx

#(if necessary yum install mercurial)
hg clone https://code.google.com/p/foamcalcex/
cd foamcalcex
./Allwmake

#usage
foamCalcEx multiplyDivide p multiply -value 1000 -latestTime   #creates p_multiply_value
ptot -latestTime  #creates ptot based on p
foamCalcEx multiplyDivide ptot multiply -value 1000 -latestTime  #creates ptot_multiply_value