MATH SYMBOLS
'(<a href="http://www.j-archive.com/media/2010-11-18_DJ_17.jpg" target="_blank">Jimmy of the Clue Crew explains an equation on the monitor.</a>) The big "E" is actually the Greek letter sigma; in math, it means to do this to a series of terms--here, from 1 to 3'
sum them (or add them)